About this lesson
The Carnot cycle is the ideal, reversible heat engine working between a hot and a cold reservoir. No real engine can beat its efficiency, so it is the benchmark every power cycle is measured against.
How it works
- Isothermal heat addition: the working fluid takes heat Q1 from the hot source at constant temperature.
- Isentropic expansion: the fluid expands, does work W and cools to the sink temperature.
- Isothermal heat rejection: the fluid gives up heat Q2 to the cold sink at constant temperature.
- Isentropic compression: the fluid is compressed back to the start, ready to repeat.
- Net work is W = Q1 - Q2, the area enclosed by the rectangle on the T-s diagram.