Clausius inequality - thermodynamics:
Whenever closed system undergoes cyclic process, cyclic integralis less than zero (that is negative) for an irreversible cyclic process and equal to zero for a reversible cyclic process.
The efficiency of reversible H.E. operating within temperature T_{1} & T_{2} can be given by:
or for a reversible engine. .......(i)
Now efficiency of irreversible H.E. operating within same temperature limit T1 and T2 can be given by
Combining equation (i) and (ii); we get d ≤ 0 The equation for irreversible cyclic process can be written as: + 1 = 0 I = Amount of irreversibility of cyclic process.