Singapore Journal of Scientific Research2010-006x2010-0051Science International10.3923/sjsres.2011.23.37AbamF.I. OnyejekweD.C. UnachukwuG.O. 1201111Exergy analysis has been applied to 138 MW in-service gas turbine plant with data obtained from plant operation. The research investigated the effect of ambient temperature on the performance of the components system of the gas turbine plant using the exergy concept, to identify components that offer significant work potential saving opportunity. The fuel used is natural gas of low calorific value of 39.4 MJ m-3. The irreversibility rate of system components, exergy efficiency and the efficiency defects were determine for each component and for the entire plant at different temperatures. The results show a moderate increase of the total irreversibility rate of plant from approximately 415 to 421 KW while the rational efficiency decreased from 16.53 to 15.44% at same temperature range of 295 to 307 K. Furthermore, a 1°C increase in ambient temperature lead to 0.43 MW increase in the total irreversibility rate and 0.3% decrease in rational efficiency. The overall breakdown of plant, efficiency defect for ambient temperature range (295-307 K) stood at 83.475-84.56, 65.06-65.18, 3.23-3.33, 8.19-8.99 and 7.0-7.06% for combustion chamber, compressor, turbine and exhaust manifold, respectively. The exergy destruction rate in the combustion chamber and the turbine was about 36.4 and 5.4%, respectively. Our computation shows exergy efficiency value of 45.43 and 68.4% for both the combustion chamber and the turbine at 14°C increase in temperature. Overall suggestions for plant improvement are made as results show that the combustion chamber and turbine are the main sources of irreversibilities in the plant.]]>Cihan, A., O. Hacihafizoglu and K. Kahveci,200630115126Ebadi, M.J. and M. Gorji-Bandpy,200523139Fiaschi, D. and G. Manfrida,199839224230Flavio, G. and A. Segioil,20004111911200Habib, M.A., S. Said and J.J. Al-Bagawi,19952011211130Kotas, T.J.,1995Kumar, N.A. and S.R. Kale,20024548314845Kwon, Y., H. Kwak and S. Oh,200113140Mahmoudi, S.M.S., V. Zare, F. Ranjiban and L. Garooci-Farshi,2009923992407Kopac, M. and A. Hilalci,20072713771385Nag, P.K.,2003Ofodu, J.C. and D.P.S. Abam,2001371428Prasada, R., P.J. Utgikar and S.P. Dubey,19952094553Rosen, M.A.,20013180192Zhang, G., B. Hua and Q. Chen,200024163618Rosen, M.A., and I. Dincer,200443121133