Idris A. Elfeituri
Exergy Based Performance Analysis of a Gas Turbine Unit at Various Ambient Conditions
777 - 786
2017
11
6
International Journal of Energy and Power Engineering
https://publications.waset.org/pdf/10007953
https://publications.waset.org/vol/126
World Academy of Science, Engineering and Technology
This paper studies the effect of ambient conditions on the performance of a 285 MW gas turbine unit using the exergy concept. Based on the available exergy balance models developed, a computer program has been constructed to investigate the performance of the power plant under varying ambient temperature and relative humidity conditions. The variations of ambient temperature range from zero to 50 &ordm;C and the relative humidity ranges from zero to 100, while the unit load kept constant at 100 of the design load. The exergy destruction ratio and exergy efficiency are determined for each component and for the entire plant. The results show a moderate increase in the total exergy destruction ratio of the plant from 62.05 to 65.20, while the overall exergy efficiency decrease from 38.2 to 34.8 as the ambient temperature increases from zero to 50 &ordm;C at all relative humidity values. Furthermore, an increase of 1 &ordm;C in ambient temperature leads to 0.063 increase in the total exergy destruction ratio and 0.07 decrease in the overall exergy efficiency. The relative humidity has a remarkable influence at higher ambient temperature values on the exergy destruction ratio of combustion chamber and on exergy loss ratio of the exhaust gas but almost no effect on the total exergy destruction ratio and overall exergy efficiency. At 50 &ordm;C ambient temperature, the exergy destruction ratio of the combustion chamber increases from 30 to 52 while the exergy loss ratio of the exhaust gas decreases from 28 to 8 as the relative humidity increases from zero to 100. In addition, exergy analysis reveals that the combustion chamber and exhaust gas are the main source of irreversibility in the gas turbine unit. It is also identified that the exergy efficiency and exergy destruction ratio are considerably dependent on the variations in the ambient air temperature and relative humidity. Therefore, the incorporation of the existing gas turbine plant with inlet air cooling and humidifier technologies should be considered seriously.
Open Science Index 126, 2017