Rankine cycle vs Carnot cycle

Carnot cycle is two reversible isothermal and two reversible adiabatic process are done in a heat engine. Rankine cycle is a thermodynamic cycle of heat engine that converts heat into mechanical work undergoing the phase change. Let us have a deep insight into the difference between the Rankine cycle and the Carnot cycle. 

Main difference :

The pressure of working fluid is raised from the pressure of condenser to the boiler pressure in Carnot cycle, whereas in the Rankine cycle, the saturated liquid is pumped to the boiler with a pump. 

Difference between Carnot and Rankine cycle :

  • The heat addition process is isothermal in case of Carnot cycle, whereas isobaric in Rankine cycle. 
  • Heat addition and heat rejection are done by keeping the temperature constant in the Carnot cycle while both are done by keeping the pressure constant in the Rankine cycle. 
  • Carnot cycle is a theoretical cycle while the Rankine cycle is a practical cycle. 
  • Rankine cycle like other cycles leads to entropy generation due to the heat transfer process, but Carnot cycle doesn’t.
  • The efficiency of the Rankine cycle is less than a Carnot cycle.
  • Carnot cycle uses air as the working substance while the Rankine cycle uses water as a working substance. 
  • Carnot cycle is an ideal cycle for heat engine while the Rankine cycle is ideal for the vapour power cycle.