A question about Thermodynamics, if someone would help with that... I understand a steam engine that follows the Rankine cycle has basically 4 steps: (a) heating in a boiler; (b) expansion on a piston or turbine; (c) condensation; (d) pump back into the boiler. For many years I have been curious why step (c) involves condensation. Couldn't I change (c) to be cooldown of the steam to a temperature just above boiling, and therefore avoid the waste of heat due to evaporating the water again? The usual explanation I find about this is that "condensation avoids the problem of controlling a two-phase mixture, and decreases the energy spent in pumping back to boiler". That explanation is fine, but it leaves me very curious why I never heard about any single steam engine that used a more efficient cycle by avoiding the liquid phase. I mean, if (c) = cooldown then that's closer to Carnot cycle, isn't it? Any help with that?