Sadi Carnot

The carnot cycle is the most efficient heat engine cycle allowed by physical laws. This idea was first expressed by Sadi Carnot. The following is an excerpt from the Wikipedia article on Carnot.

"Sadi Carnot (1796 -1832) was a French military scientist and physicist, often described as the "father of thermodynamics". Like Copernicus, he published only one book, the Reflections on the Motive Power of Fire (Paris, 1824), in which he expressed, at the age of 27 years, the first successful theory of the maximum efficiency of heat engines. In this work he laid the foundations of an entirely new discipline, thermodynamics. Carnot's work attracted little attention during his lifetime, but it was later used by Rudolf Clausius and Lord Kelvin to formalize the second law of thermodynamics and define the concept of entropy."