4 ms·

I wondered if it was necessary to boil water

• dredmorbius 12y ago
  It's not necessary, but it's a good route. You could run a Stirling-cycle engine off a hot and cold end without a phase-change working fluid. But gas turbines are very efficient (and simple), and work best when working with the very high-level pressure gradient presented either by combustion (as with a jet engine) or live steam (with a pressure drop in the condensed state) as with a steam turbine. You could substitute other volatile working fluids, but water is cheap, abundant, and provides useful work at temperatures typically attainable in systems -- 100 - 1000 C (typically in the 200 C - 500 C range).