Sadi Carnot

Physicist and engineer — Nicolas Léonard Sadi Carnot (Paris 1796 – 1832) was a French physicist and engineer, regarded as the father of thermodynamics. Son of the mathematician and statesman Lazare Carnot, he trained at the École polytechnique and served in the army as an engineer. In 1824 he published the work ‘Réflexions sur la puissance motrice du feu’, in which he analysed for the first time, in a theoretical way, the efficiency of heat engines, introducing the concept of the ideal reversible cycle. He showed that the maximum efficiency of a heat engine depends only on the temperatures of the two reservoirs and not on the working substance, anticipating the second law of thermodynamics. He died very young of cholera, and only after his death were his ideas taken up and developed by Clapeyron, Kelvin and Clausius.

Trivia

He died of cholera at only 36, and, for fear of contagion, many of his manuscripts were buried with him, thereby lost to science.

Theories and contributions

• Carnot cycle — An ideal reversible thermodynamic cycle made up of two isothermal and two adiabatic transformations, representing the heat engine of maximum efficiency.
• Carnot’s theorem — The maximum efficiency of a heat engine depends only on the temperatures of the reservoirs: $\eta = 1 - \dfrac{T_f}{T_c}$.

Appears in chapters

10 11 12 Z

Linked atoms

9 linked atoms.

10 Trasformazioni irreversibili e bilancio energetico

• Heat: from the invisible fluid to the dance of energy accounts

11 Entropia

• The reversible cooling of coffee

12 Cicli e macchine termiche

• The price of work
• Why Carnot is a beacon
• Named cycles
• Sadi Carnot: a historical note
• The Carnot cycle and maximum efficiency
• Refrigerators and heat pumps

Z Appendice — Maturità

• Key formulae: Thermodynamics