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Air travel produces around 2.5% of all global CO2 emissions, and despite decades of effort in developing alternative fuels or more efficient aircraft designs, that number hasn\u2019t budged much. However, NASA, also the US\u2019s Aeronautics administration, has kept plugging away at trying to build a more sustainable future for air travel. Recently, they supported another step in that direction by providing an Institute for Advanced Concepts (NIAC) grant to Phillip Ansell of the University of Illinois Urbana-Champaign to develop a hybrid hydrogen-based aircraft engine.<\/p>\n
<\/p>\n The grant focuses on developing the Hydrogen Hybrid Power for Aviation Sustainable Systems (Hy2PASS) engine, a hybrid engine that uses a fuel cell and a gas turbine to power an aircraft. Hybrid systems have been tried before, but Hy2PASS\u2019s secret sauce is its use of air handling.<\/p>\n In hybrid aircraft systems, there\u2019s typically a fuel cell and a gas turbine. The fuel cell takes hydrogen as an input and creates electrical energy as output. In a typical hybrid system, this electrical energy would power a compressor, whose output was directly coupled to turning the turbine. However, in Hy2PASS, the compressor itself is decoupled from the turbine, though it still supplies oxygen to it. It then also supplies oxygen to the fuel cell\u2019s cathode, allowing for its continued operation.<\/p>\n \n