Exergy analysis of NEKA-IRAN heat recovery steam generator at different ambient temperatures

The supplementary firing is one of the techniques which are used to increase the output power of the combined cycle power plants (CCPP). The low construction cost per generated power encourages designers to consider it in the new CCPP. In this paper exergy analyses of HRSG with and without supplementary firing are presented. They are based on the performance test data at different operating conditions. The objective of these analyses is to present the effects of supplementary firing on gross power output, combined cycle efficiency and the exergy loss in Heat Recovery Steam Generator (HRSG) devices at different ambient temperatures. The results show that the most effective components for the exergy losses are stack, LP-EV and LP-SH at different ambient temperature. The effect of the supplementary firing on the exergy loss has been studied as well. The results reveal that although the supplementary firing increases the gross output power of the combined cycle power plant, however it increases the total exergy loss of HRSG and consequently decreases the total exergy and thermal efficiency.