Advanced exergy analysis of an electricity-generating facility using natural gas Emin Açıkkalp a,⇑ , Haydar Aras b , Arif Hepbasli c a Department of Mechanical and Manufacturing Engineering, Engineering Faculty, Bilecik S.E. University, Bilecik, Turkey b Department of Mechanical Engineering, Engineering and Architecture Faculty, Eskisehir Osmangazi University, Eskisehir, Turkey c Department of Energy Systems Engineering, Engineering Faculty, Yasar University, Izmir, Turkey article info Article history: Received 5 December 2013 Accepted 1 March 2014 Available online 27 March 2014 Keywords: Exergy analysis Advanced exergetic analysis Exergy destruction Electricity generation facility abstract This paper deals with the performance assessment of an electricity generation facility located in the Esk- isehir Industry Estate Zone in Turkey using advanced exergy analysis method. The exergy efficiency of the system is determined to be 40.2% while the total exergy destruction rate of the system is calculated to be 78.242 MW. The exergy destruction rate within the facility’s components is divided into four parts, namely endogenous, exogenous, avoidable and unavoidable exergy destruction rates. Through this anal- ysis, the improvement potentials of both the components and the overall system along with the interac- tions between the components are deducted based on the actual operational data. The analysis indicates that the combustion chamber, the high pressure steam turbine and the condenser have high improve- ment potentials. The relations between the components are weak because of the ratio of the endogenous exergy rates of 70%. The improvement potential of the system is 38%. It may be concluded that one should focus on the gas turbine and combustion chamber for improving the system, being the most important components of the system. Ó 2014 Elsevier Ltd. All rights reserved. 1. Introduction Gas turbines consist of a compressor, a combustion chamber and a turbine while they have been widely used in the industry and transportation sectors. For example, they are used in energy production facilities, aircrafts, transport ships, and even cars and motorcycles. Gas turbines have some particular advantages, such as low annual cost, fast activation, flexible operation, and fast and easy maintenance. In addition, the most important advantage of gas turbines is that their efficiency is high (approximately 40%). Unfortunately, gas turbines also have disadvantages. Gas turbine maintenance costs are high, they are sensitive to ambient condi- tions, and they are sensitive to electricity voltage change. Gas tur- bines are primarily used in combined heat and power (CHP) generation facilities in industry. CHP facilities produce electricity and heat energy from one type of fuel, generally natural gas. The efficiency of such a facility can reach 70–80% [1]. In addition to the economic and efficiency benefits, their environmental impact is an important factor. Gas turbines have low greenhouse gas emis- sions compared to many other power generation systems. All energy conversion systems must be analyzed in terms of energetic, economic, and environmental aspects for a proper man- agement. Exergy-based analyses are very convenient methods for assessing the performance of energy conversion systems. Exergy is the maximum work that can be obtained from a system. Exer- gy-based analyses help determine the irreversibilities (entropy generation) and how a source can be used effectively. However, exergy-based analyses lack some information, which will be dis- cussed in Section 3.2 in more detail. Basically, the results of an exergy-based analysis cannot be used to consider the potential improvement of the system or its components, and they do not provide any information about how one component affects one an- other. This lack of information can be addressed through advanced exergy-based methods [2,3]. There are a few studies on advanced exergy-based analyses of power-generating systems in the open literature [3–15]. Tsatsaro- nis [3] discussed the weaknesses of conventional exergy-based analyses in developing improvement strategies and presented ad- vanced exergy, advanced exergoeconomic and exergoenvironmen- tal analyses as solutions to these weaknesses. Tsatsaronis and Moung-Ho [4] were the first to develop the concepts of avoidable and unavoidable exergy destruction, which were used to deter- mine the potential of improving the thermodynamic performance and cost effectiveness of a system. Cziesla et al. [5] investigated http://dx.doi.org/10.1016/j.enconman.2014.03.006 0196-8904/Ó 2014 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. Tel.: +90 (228) 2160061; fax: +90 (228) 216 05 88. E-mail addresses: eacikkalp@gmail.com, emin.acikkalp@bilecik.edu.tr (E. Açıkkalp). Energy Conversion and Management 82 (2014) 146–153 Contents lists available at ScienceDirect Energy Conversion and Management journal homepage: www.elsevier.com/locate/enconman