otherclive said:
My first job after completing an Application Course was to manage the Turbine and ICE shops in Devonport. We had a steady stream of Deltics, Paxman Ventura and Valenta plus ASR1 to overhaul. Most of them were problematic in one way or another.
Then when I returned to the Naval College the dear Stirling engine was thought to be the answer to the submariners dream of silent running.
Nice simple external combustion engine, very quiet, but hopelessly inefficient, and difficult to scale up from small models to produce practical output powers. Various attempts to improve them including pressurising the internal volume, but I don't know of anything bigger than about 40HP, .
The victorians had a good use for them,
https://www.google.com/url?sa=i&source=images&cd=&ved=2ahUKEwjytcrx_ZnkAhVBTBoKHS1DCXgQjRx6BAgBEAQ&url=https://www.youtube.com/watch?v=1MTIyb2ycv4&psig=AOvVaw2VVLAs0ovob7yCYDUQfGhL&ust=1566683660806625
they made dtove top versions to drive a a fan to circulate warm air around a room. Modern equivalents use a peltier thermo electric chip powering an electric motor.