The Mechanical Tracker is pretty interesting. Though, I think the mirror on the top with the parabolic dish is what makes this not attractive to get. The guy does mention that if the unit doesn't start tracking in the morning, it can't catch up. So if there's a storm or overcast in the early and it clears up by 10 or noon, you loose power production for the rest of the day. That's very negative results in my opinion and what would keep me from getting this system.
If they changed the way the tracker collects sun heat in the first place, that would make this more enticing.
My uncle knew a guy years ago that used freon as a tracker driver. The basic principle is that as the freon is heated, it expands, much like the parrafin wax in the above unit. But this guys unit was more vertical and would track no matter time of the day. If the sun heat was available after noon, it would heat up and push the panel to the optimal angle for that given time. Then in the evening as the freon cooled, it would pull the panel(s) back to reset.
I'm sure this could also be figured out to use the paraffin wax as well.
