3D metal printing is coming along nicely. A 3D-printed mini jet engine that performs at 33,000 RPM http://www.kurzweilai.net/a-3d-printed-mini-jet-engine-that-performs-at-33000-rpm
I like the idea of a micro turbine gen set for the Hot Cat better than the seemingly more popular Stirling engine. There are quite a range of these in commercial use now. It seems to me relatively simple to replace the natural gas heating by Hot Cats.
I thought this was neat example of a very small one. (400 W) https://youtu.be/Al8elCF816g
