Definition: Carnot Engine

The Carnot engine is a Heat Engine based on an ideal gas which undergoes the following Carnot cycle:

  1. The gas expands isothermally at Temperature , absorbing Heat .
  2. The gas expands adiabatically until its temperature drops to .
  3. The gas is compressed isothermally at temperature , releasing heat .
  4. The gas is compressed adiabatically back to temperature .

Theorem: Thermal Efficiency of the Carnot Engine

No Heat Engine can have a higher Thermal Efficiency than that of a Carnot Engine, which is given by the Temperature of the hot reservoir and the temperature of the cold reservoir as follows: