Thermo-environmental analysis of an open cycle gas turbine power plant with regression modeling and optimization Abdul Ghafoor Memon a, * , Rizwan Ahmed Memon a , Khanji Harijan a , Muhammad Aslam Uqaili b a Department of Mechanical Engineering, Mehran University of Engineering and Technology, Jamshoro 76062, Pakistan b Department of Electrical Engineering, Mehran University of Engineering and Technology, Jamshoro 76062, Pakistan article info Article history: Received 29 April 2013 Accepted 17 June 2013 Available online 29 March 2014 Keywords: gas turbine exergy regression optimization abstract In this paper, a gas turbine cycle is modeled to investigate the effects of important operating parameters like compressor inlet temperature (CIT), turbine inlet temperature (TIT) and pressure ratio (PR) on the overall cycle performance and CO 2 emissions. Such effects are also investigated on the exergy destruction and exergy efficiency of the cycle components. Furthermore, multiple polynomial regression models are developed to correlate the response variables (performance characteristics) and predictor variables (operating parameters). The operating parameters are then optimized. According to the results, operating parameters have a significant effect on the cycle performance and CO 2 emissions. The largest exergy destruction is found in the combustion chamber with lowest exergy efficiency. The regression models have appeared to be a good estimator of the response variables. The optimal operating parameters for maximum performance have been determined as 288 K for CIT, 1600 K for TIT and 23.2 for PR. Ó 2014 Energy Institute. Published by Elsevier Ltd. All rights reserved. 1. Introduction The gas turbine based power plants are receiving considerable attention due to their shorter lead time, operational flexibility and lower greenhouse gas emissions. To optimize such plants, it is important to find and quantify the operating/design parameters through some thermodynamic analysis that may ultimately improve thermodynamic performance and mitigate environmental impact. Many researchers have reported that the performance of gas turbine cycles is strongly influenced by compressor inlet temperature (CIT), turbine inlet temperature (TIT), pressure ratio (PR), air-to-fuel-ratio and isentropic efficiencies of air compressor and gas turbine [1e3]. In addition to energy analysis, exergy analysis has become an increasingly important thermodynamic tool for the design and analysis of energy systems and many researchers have suggested the use of exergy analysis in the evaluation of thermodynamic performance of any energy system for efficient utilization of energy resources and small environmental impact [4e7]. The primary goal of exergy analysis is to identify the ir- reversibilities occurred mainly because of chemical reactions, heat transfer and friction in the systems. The exergy analysis has been widely applied to many gas turbine based power plants [8e13]. According to the results, the plants’ exergy efficiency, exergy destruction, power-to- heat ratio, and specific fuel consumption are greatly influenced by the operating parameters, and that the combustion chamber is a major contributor in the exergy destruction of the plants [8e13]. Global warming, especially due to CO 2 emissions is one of the environmental challenge humanity faces today. Use of fossil fuels for power production is considered as a prime source of CO 2 emissions; in fossil fuels the emissions from coal are the highest and that from natural gas the least. Therefore, researchers are keen to explore different environmental impact mitigation strategies while exploiting fossil fuels for power production [7,14]. In the current article, a greater focus has been placed on the gas turbine cycle. In this regard the thermodynamic and environmental analyses of an open cycle gas turbine power plant are carried out in order to investigate the impact of important operating parameters, CIT, PR and TIT on the performance characteristics like net power output, fuel consumption, energy and exergy efficiencies, and CO 2 emissions. The impact of operating * Corresponding author. E-mail addresses: ghafoor.memon@faculty.muet.edu.pk (A.G. Memon), rizwanhashmani@yahoo.com (R.A. Memon), khanji.harijan@faculty.muet.edu.pk (K. Harijan), aslamuqaili@yahoo.co.uk (M.A. Uqaili). Contents lists available at ScienceDirect Journal of the Energy Institute journal homepage: http://www.journals.elsevier.com/journal-of-the-energy- institute http://dx.doi.org/10.1016/j.joei.2014.03.023 1743-9671/Ó 2014 Energy Institute. Published by Elsevier Ltd. All rights reserved. Journal of the Energy Institute 87 (2014) 81e88