Can one build a Carnot Cycle engine?
No, not really. There are too many technical problems. For example, you would have to heat the gas to the same temperature as the source but heat won’t flow into the gas unless the gas is cooler than the source. All of the heat energy in the gas should go into pushing the piston but some of it will go into heating up the cylinder. To work perfectly the engine would have to run very slowly. And so on.
