Khaliq and Kaushik  presented the second-law approach for the thermodynamic analysis of the reheat combined Brayton/Rankine power cycle. Expressions involving the variables for specific power-output, thermal efficiency, exergy destruction in components of the combined cycle, second-law efficiency of each process of the gas-turbine SB 216763 and second law efficiency of the steam power cycle have been derived. From there results, it was found that the exergy destruction in the combustion chamber represents over 50% of the total exergy destruction in the overall cycle. They also investigated the effects of process steam pressure and pinch point temperature used in the design of heat recovery steam generator and reheat on energetic and exergetic efficiencies .
Cihan et al.  performed energy and exergy analysis of operating combined cycle power plant to identify the potential for improving efficiency of the system. The results showed that the combustion chambers, gas turbines and heat recovery steam generators (HRSG) were the main sources of irreversibilities representing more than 85% of the overall exergy losses. Butcher and Reddy  investigated the performance of a waste heat recovery power generation system based on second law analysis for various operating conditions. The effect of pinch point on the performance of HRSG and on entropy generation rate and second law efficiency were also investigated. Butcher and Reddy found from results that the second law efficiency of the HRSG and power generation system decreases with increasing pinch point.