Starting with Eq. 10-20, show that the exergy destruction associated with a simple ideal Rankine cycle can

Question:

Starting with Eq. 10-20, show that the exergy destruction associated with a simple ideal Rankine cycle can be expressed as xdest = qin(th,Carnot - th), where th is efficiency of the Rankine cycle and th,Carnot is the efficiency of the Carnot cycle operating between the same temperature limits.