I’m just a bit skeptical about their -20% fuel burn claims
FWIW I had opportunity to speak with a guy in the business today about increasing efficiency on small turbine aircraft engines. He immediately started talking about flight weight recuperators, which would recover waste heat from the exhaust to improve cycle efficiency. It hasn’t gone anywhere because the whole engine needs to be redesigned and there’s a perception that you can’t do it within a reasonable weight budget. He thinks you could, and in doing so would much improve SFC.
There is info on the web if interested, for instance Link and Link