I am getting a little obsessed with Stirling engines. This all started when R and I were playing around with generating power from temperature differentials using Peltiers. (Peltiers are solid state devices that can either create temperature differences from electrical input, or create electricity from existing temperature differential.) We got to talking about the potential of temperature differential to generate electricity for a variety of purposes. That anytime you have something that’s hot, and the surrounding air is cooler, a Peltier could turn that into energy. I had this idea that you could attach something to the side of a cooking pot in a low resource environment, and then somehow harness the excess heat from the wood or charcoal fire that is never used by the actual cooking activity. Thinking of all that heat and energy that dissipates into the air, it seemed like there had to be a way to harness that and put it to good use, especially in places that didn’t have grid electricity.
Working one day on trying to charge a cellphone off of candles and Peltiers, one of our friends said, ‘why not try a Stirling Engine?’ Since I didn’t actually know what that was, all I could do was stare blankly.
But the Stirling Engine is a totally cool thing. It’s an old mechanical device — one of my favorite kind of things, old, overlooked technology. Few moving parts, and thus user servicable in a low resource setting (one of the limitations of the Peltiers were their lack of user servicability and thus their tendency to become bricks once they fail).
I have this image in my mind of a cooking pot lid with a stylized handle which is actually a Stirling engine. So you could charge your cellphone in while the beans boiled.
It turns out Stirling engines are actually a little fussy. And the real problem is that eventually the cook side gets heated and the magic of that temperature differential gets lost. But I haven’t given up on the Stirling engine. Or the Peltiers. Not yet.