This seems possibly not crazy. If you can have one of these powered by natural gas and scale it to 20 kW then you have a nice home generator that is "whisper quiet" according to TFA and also: simple, easy to maintain, with few moving parts, perhaps even durable. The hydrogen aspect of this is not as interesting as the other fuels, though it'd be nice to know the efficiency numbers for different fuel types. That said, having to supply sodium might be a problem.
I wonder if they recover the sodium and run it back through the process.
For that matter, could you maybe put sodium in a sealed container and then heat the whole container? Like a sodium vapor lamp but causing it to glow by throwing heat at it instead of passing electricity through it.
indeed yes; the sodium is added as sodium chloride. in molten form, it wicks along sapphire and alumina surfaces, similar to a candle. it reforms into sodium chloride as the temperature drops below its boiling point -- 1400 C.
we're exploring fully sealed experiments, but, you have to get the heat into the sealed cell somehow.
aha, i was wondering how that worked. Creating pure sodium using the Downs process requires a lot of electricity and I doubt this engine would be economic if that was required. But it looks really promising, >= 40% efficiency is a great goal.
If such a generator were powered by nat gas rather than being a battery of sorts, then even being a bit less efficient than an ICE would be attractive if the generator were simpler and had a lower TCO than the ICE equivalent.
