Heat engine is a device which converts heat energy into mechanical energy.
In the year 1824, Carrot devised an ideal cycle of operation for a heat engine. The machine used for realizing this ideal cycle of operation is called an ideal heat engine or carrot heat engine. The essential parts of a Carnot engine are shown in Figure.
(i) Source
It is a hot body which is kept at a constant temperature T1 has infinite thermal capacity. Any amount of heat can be drawn from it at a constant temperature T1 (i.e) its temperature will remain the same even after drawing any amount of heat from it.
(ii) Sink
It is a cold body which is kept at a constant lower temperature T2. Its thermal capacity is also infinite that any amount of heat added to it will not increase its temperature.
(iii) Cylinder
Cylinder is made up of non-conducting walls and conducting bottom. A perfect gas is used as a working substance. The cylinder is fitted with a perfectly non-conducting and frcitionless piston.
(iv) Insulating stand
It is made up of non conducting material so as to perform adiabatic operations.
Working: The Carnot engine has the following four stages of operations.
- Isothermal expansion 2. Adiabatic expansion 3. Isothermal compression 4. Adiabatic compression.