Question

What are Carnot Cycle, Stirling Cycle, and Otto Cycle ?

Answer 1

A thermodynamic cycle consists of a linked sequence of thermodynamic processes that involve transfer of heat and work into and out of the system, while varying pressure, temperature, and other state variables within the system, and that eventually returns the system to its initial state.

Every single thermodynamic system exists in a particular state. When a system is taken through a series of different states and finally returned to its initial state, a thermodynamic cycle is said to have occurred. In the process of going through this cycle, the system may perform work on its surroundings, thereby acting as a heat engine.

There are four steps in each engine. Steps of Carnot cycle, Stirling cycle, Otto Cycles are as below:

Cycle Process 1-2 Process 2-3 Process 3-4 Process 4-1

(Compression) (Heat Addition) (Expansion) (Heat Rejection)
Carnot isentropic isothermal isentropic isothermal Carnot heat engine
Stirling isothermal ​ isochoric isothermal ​isochoric ​Stirling engine
Otto adiabatic ​ isochoric adiabatic ​isochoric Gasoline / petrol engines