Hmmm. Car radiators/heatercores and A/C coils are designed for forced convection cooling, ie. with fans. Therefore the fins are very closely packed, and I would doubt that relying on natural convection to get the air through them would be very effective.
Thenagain, I suppose this is compensated somewhat by the increased surface area...
What I want is a radiator *designed* for natural convection
and that won't cost an arm and a leg (the cheapest of those Innovatek radiators is already 100€, and this one is just too small IMO)
Now if I could just get hold of some of that finned aluminium tubing...I wish
