1 March 2008 — dan

Yes, this MSI motherboard northbridge fan powered by a teeny little Stirling engine is very neat.

I hope it makes it into production, and I also hope it's well enough made that it'll last at least as long as the crappy electric fans you usually get on a northbridge heat sink.

Small Stirling engines like this have very little power, and they need to be manufactured to very fine tolerances if you want them to run on a small-ish temperature differential - like, on top of a CRT or even LCD monitor, or on the heat of your hand for fancier models.

I've got one that runs fine on a cup of tea, but it isn't smooth enough for anything better. You need something like the above engine, with glass cylinders and graphite pistons, to get really low-temperature-differential operation.

A modern motherboard main-chip, though, will easily give enough heat to run a small Stirling fan, and it shouldn't need much wind over a good-sized heat sink like this to keep it at an acceptable temperature (actually, the Stirling fan may pretty much be just tinsel - the normal air flow through the case may be plenty to keep the northbridge cool, with a heat sink that big).

So the goofy MSI rig actually ought to work quite well even with a relatively cheaply-made Stirling engine. And if the engine craps out after a few months, you can always bodge a normal fan in there to replace it.

(Or do so immediately, so you can take the engine out and display it on top of your coffee cup instead.)

The product this little fan most reminds me of is the Heat Wave wood stove fan, which takes advantage of the large temperature differential between the top of a combustion stove and the ambient air to run a robust, long-lived Stirling engine with enough power to circulate air quite effectively, which can considerably improve the room-inhabitant-heating effectiveness of the stove. There are similar, cheaper products based on Peltier elements and boring electric motors, but c'mon, stump up the extra for the piston motor. You know you want to.

Dammit. Now I want a glass-and-graphite low-temperature Stirling engine.

Or maybe one of the Böhm kits.

Or the Gakken version, to add to my collection.

Or their steam car (note, regrettably, that neither this kit nor the Vacuum Engine car actually come with a Wondermark-ish top-hatted figurine to ride them).

(Note that all this does not mean that PC-powered steam engines are just around the corner.)