IntroductionThis cycle was proposed in 1824 by a Germanengineer “SADI CARNOT”.It is a hypothetical cycle which is used to compareother cycle.It consist of four reversible process.
AssumptionsWorking substances is a perfect gas.There is no friction between the cylinder andpiston.Walls of cylinder and piston are considered asperfect heat insulator.Transfer of heat does not affect the temperatureof source or sink.
Elements of Carnot cycle Working substances. (i.e. Air)Heat source and heat sink.Piston-Cylinder arrangement.Diathermic cover (perfect heat conductor) andAdiabatic cover (prefect heat insulator)
WorkingIt works on 4 steps. (i.e. 2 isentropic(adiabatic) & 2isothermal).
Efficiency of Carnot cycleEfficiency of Carnot cycle = work done /heatsuppliedEfficiency of Carnot cycle depends upon thetemperature range. = 1-(T2 /T1)Efficiency increase with decrease intemperature.
Impractibility of Carnot cycleIt is impossible to perform a frictionlessprocess.It is impossible to transfer the heat with outfinite temperature difference.During isothermal the piston move very slowlyso that temperature remains constant & duringadiabatic process it moves very fast so heattransfer is negligible due to very short timeavailable. The variation of speed during thesame cycle is not possible.