Interestingly, the steam engines of the Titanic made use of the vacuum generated by condensing steam to extract additional energy from steam that's below atmospheric pressure.
https://www.titanicology.com/Titanica/TitanicsPrimeMover.htm
https://www.titanicology.com/Titanica/TitanicsPrimeMover.htm
I can come to a thread, and almost always there will be somebody replying with extra information on the topic at hand.
Thank you.