Nowadays the difference between the supply and demand of energy continuously rises.Thus finding
new energy resources and also using present resources more efficiently are the key concepts of the new century.One of the ways to use energy resources more efficient is to produce electrical energy from combined cycle power plants.In order to maintain the efficient operating conditions of the plants,
performing performance analysis is a requirement. In this study a performance analysis of an operating power plant is performed with actual operating data acquired from power plant control unit.The
analysis is performed by using first and second law thermodynamics. Energy and exergy efficiencies of
the each component of the power plant system are calculated and also parametric analysis is performed.
After applying first law and second law of thermodynamics, energy and exergy efficiencies of the
combined cycle power plant are found as 56% and 50.04% respectively and it is found that combustion
chamber has the most exergy destruction rate among the system components. According to the
calculation results, improvement and modification suggestions are presented.