paganizer's Journal: Sterling cycle cooler for CPU's

A weird idea occured to me a while back, and I've started playing with it.
I've had problems with CPU fans since they existed; by nature they can't help but get gunked up with crap on a pretty regular basis.
Since I have a few projects which require processors to run at 100% for extended periods of time, I've been thinking about different ways to fix this problem.
What I have come up with is building a small sterling cycle engine powered by the heat of the CPU(s), which supplies electricity for the large fans outside the case; the engine itself will draw a measure of heat away fom the processor, and the electricity produced should provide enough oomph to blow away the rest.
When the usage is low, the chip is cool, and the fans idle; when hot, there is more airflow.
I am currently going with a 12" shrouded (with a filtered intake) fan blowing into a section of 4" flex tube, which is affixed to a dremeled hole in the top of a midi-tower case; this is amazingly effective so far (it's not sterling powered yet, just hooked up to the power supply); a 1.1ghz Athlon (with just a heatsink) that is rendering in 3Dstudio stays in the 39-42 degree C range.
I fully plan to stay with pushing air into the case; this should result in a perpetual "overpressure" situtation, and should prevent any dust buildup, as long as the duct system is pushing air in with more force than the power supply fan.
Eventually, I would think the fan could be prettied up, and possibly be mounted on the back of the display.