Videodemonstraton sieht für den ersten Prototypen doch sehr vielversprechend aus.
Wünsche euch viel Erfolg!

The GEH1.0 is only the first step. The next step is a mashine that cut the failed-3d-printed object in smal particles, and then you can feed the GEH1.0 with that smal particles (mixed with some new granulat to get a good material) Thats real recycling ;-)

I still see the "extrude as 1.75mm filament" as a better option to feed every ordinary printer instead of a specialized printer - this way you'll get more potential customers / a bigger market and don't have to hassle with the actual 3D printing. 

Or you use the "its not so good for small nozzles (0.3, 0.2, 0.1)" disadvantage for your advantage and aim for big prints and rapid rapid prototyping. 

Why not use the extruder in conjuction with some airflow to let the extruded filament settle while spooling it?

The o̶n̶l̶y limitations would, of course, be the extrusion speed and slight inperfections. That's a given anyway with homebrew machinery but the potencial is there I assume.

Since I am in no way an expert in 3D printing please feel free to correct me.

Why don't you use this head to extrude 1.75mm filament instead? I'd love to have a little machine where I can throw in failed prints and support material and get recycled filament out of it. I don't always care about the color of the print anyway...

we want to develope a way to act environment aware and save money. 

By quickly changing the GEH 1.0 on your printer platform,
the advantaged of both techniques (filament and granulate) can be combined and
used in an optimal way.