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.
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.