Seems to me that since Minto's wheel operates off a temperature
differential, you couldn't consider it overunity unless you created
TWO temperature regions and kept one hotter (by at least 3 degrees F i
assume) than the other. The entire device (the wheel and equipment to
create the temperature regions from its motion) would need to be
insulated to an extent where the system would be reasonably close to a
thermodynamically 'closed' system. If the wheel appeared overunity
under those conditions, i think it would be reasonable to call it
overunity.
Hoping that made sense..
Ian Webb