Peltier powered fan
A Peltier element can not only cool your CPU, it can also be used as
The efficiency is low, but that doesn't matter.
I am using peltier cooler element from eBay, and a Tamiya Model Tools 76005 SOLAR MOTOR 2, also from eBay. This motor requires less than half a volt to start spinning.
Solar motor specifications.
Solar motor real size.
I heated a 10mm thick piece of aluminium to bend it according to the diameter of the exhaust pipe on my furnace, 160 mm.
A flat surface 40 mm wide provides the contact area to the peltier.
Milling of the flat surface.
On the cool side of the peltier I placed a surplus AMD Opteron CPU cooler.
The CPU cooler on top of the peltier.
The solar motor is mounted to a 2mm aluminium bracket milled out.
Milling of bracket.
Peltier powered fan assembly.
The propellers starts spinning about 5 minutes after a fire is started, and continues to spin for as long as the exhaust pipe is hotter than the CPU cooler.
The fan is 10x8.25 from hobbycity, and spins 500 rpm, according to my handy rpm meter.