Stirling cycle

The Stirling cycle is a thermodynamic cycle that can be invented by Robert Stirling in 1845.

What is the Stirling cycle?

In the Stirling cycle, two isothermal processes and two constant volume process are done in a heat engine. Constant volume process is performed with the help of a re-generator to make this cycle reversible.

Stirling cycle PV and TS Diagram

Process of Stirling cycle :

The Stirling cycle consist of four processes following below :
  • reversible isothermal gas expansion process is heat addition process from the external source so work is done during this process.
  • constant volume heat transfer process is internal hear transfer takes place from the gas to the re-generator.  
  • reversible isothermal gas compression process is heat rejection to the external sink.
  • constant volume heat transfer is internal heat is transfer from the re-generator to a gas. 

The efficiency of the Stirling cycle :

The efficiency of the Stirling cycle is the same as that of the Carnot cycle. This is due to the fact that this cycle is also reversible as Carnot cycle. So remember that all reversible cycle have the same efficiency.

                                         Ŋcycle = Wnet / Q =  T1 – T2 / T

Also, the COP of the Stirling cycle and Carnot cycle are the same.