Gear demo: https://youtu.be/WQ8Kq8Ge7BE
Does it work? Yes!
Will the wind it produces cool you off, more than the effort of squeezing it will heat you up? I'm not sure!
Fun tech demo, anyway.
To keep it spinning you will have to smooth the insides of the wheels where they meet the axles, with either sandpaper or a rasp. I also used silicon lubricant.
Held together with M3 screws, 10mm x 3.