[Bob.Kerns]

Kamen didn't invent the Stirling engine, but he's been working on making it more practical. A counterflow heat exchanger that also serves as the boiler of a still makes so much sense I find it hard to believe it's not a part of the package.

There's a downside here. Burning fuel has environmental consequences. Deforestation, air pollution, toxic waste. That can all be offset by replacing traditional fuel uses with more efficient ones, but there's always unintended consequences to consider.

While you could use, say, thermite as a fuel, all traditional fuels except charcoal and coal produce water when they burn, as they do contain hydrogen. (And if you heat coal or charcoal, and pass steam through it, you get coal gas -- which then burns and produces water again).

If you bring down the cool side of the Stirling engine down to near the inlet temperature of the water, you could then, on the hot side, heat it with heat from the condensation side of the still. But that doesn't make any sense, because you'd need a lot of water flow to bring it down that much.

It would make more sense to me to preheat the combustion air, thus raising the hot side temperature, and making the combustion more efficient (and cleaner). At the same time, you're making the distillation more efficient (or making the cooling you're already doing more efficient -- for example, you could drive that airflow via convection with a tall chimney).

I have no idea what Dean's doing, I'm just being an engineer. But I'd love to see. I'll have to check for patents when I get a chance.