Keywords: natural gas, combined cycle power generation, energy analysis, exergy analysis, exergetic efficiency, irreversibilities, supplementary firing, gas turbines, inlet temperature, pressure ratio
Exergy analysis of a natural gas fired combined cycle power generation unit
Combined cycle power generation units are becoming popular due to their higher energy conversion efficiency and reduced pollutants and greenhouse gas emissions. In the present work, exergy analysis of a natural gas fired combined cycle power generation unit is performed to investigate the effect of gas turbine inlet temperature and pressure ratio on exergetic efficiency for the plant and exergy destruction/losses for the components. For a fixed gas turbine inlet temperature, an optimum pressure ratio exists where the exergy destruction is minimum. The exergy analysis provides the details on exergetic efficiency, exergy loss and destruction for individual components in the plant and for the overall plant and their variation with operating parameters.