Analysis and optimization of the parameters affecting the thermoeconomic performnace of gas turbines

Nowadays, utilizing energy in an efficient way has become one of the most current problems of the world. Therefore, studies related to energy efficiency are decreasing the energy consumption per unit energy production without wasting the energy sources. Thermodynamic studies based on energy provide information about the quality and the quantity of the energy, but they don?t supply a concrete approach for the efficiency of the produced energy. As a result of studies, a new science field has emerged so-called thermo-economics. Thermoeconomics, that has the optimization and analysis methods for the maximum energy production by the minimum energy cost, was composed of thermodynamics and energy-economics. Thermoeconomics studies in the literature are generally analyzing the interrelation of thermodynamic parameters of unit energy production with the energy cost. However, these studies are not sufficient for energy efficiency analysis as well. Another contemporary problem of our world is the global warming. There are many serious studies on it. The main reason of the global warming is not consuming the fossil fuels efficiently. Fossil fuels are the primary energy sources and they are used for energy production in power plants. Fossil fuels which have the greatest effect on air pollution are attracting the attentions not only for the highest production and transportation costs but also for their environmental costs due to destructive effect on nature and the organisms. Scholars started to take into consideration of the costs caused by the environmental pollution which was getting a global threat. But, the majority of the work of the environmental costs in the literature mostly considered for the analysis of the external or social costs and they are evaluated as a single cost component. The environmental costs should be included in the unit energy costs produced by the power plants. However, the environmental costs are excluded in the thermo-economic models and they are not considered inside the thermo-ecenomic analysis and optimization procedures. This situation does not permit to analyze the environmental costs due to negative effects of power plants on the environment. In this work, an environmental cost model is proposed and has been integrated into the classical thermo-economic model, the finite time thermo-economic model and exergo-economic analysis methods. The proposed environmental cost model in this study is based on the cost due to air pollution caused by the harmful exhaust gases emitted into the atmosphere by the combustion of fossil fuels. Therefore, the total cost is composed of the fuel costs, initial costs, maintenance costs, and environmental cost components. Thus, numerical analysis of the environmental effects became possible by including the environmental costs into the model for unit energy production of the power plants. The environmental cost models are addressed in three different sections of the dissertation and theoretical application of the closed-cycle, regenerative and non-ideal (with pressure loss) irreversible gas turbines are carried out and numerical studies for the analyses and optimization of the parameters that affect the thermo-economic performance are carried out for the gas turbines. An objective function is defined as the plant?s net power output of unit cost for the optimization of the model power plant. The dissertation consists of five chapters. The general information about the environmental cost and power plants are given in the Chapter 1. Analyses and the optimization according to the classical thermo-economic model are performed in Chapter 2. In Chapter 3, thermo-economics approach method based on the finite time thermodynamics is utilized, where; the environmental cost is defined as a component of the total cost by the unit entropy generation and the unit entropy generation cost of the plant. In Chapter 4, the exergo-economics analyses method is applied. The total exergy cost is composed of the stream line exergy costs, fuel exergy costs, exergy destruction costs, and the environmental exergy cost components. The environmental exergy cost is defined as a cost component which includes the chemical exergy of exhaust gasses. Exhaust gas exergy values and exhaust gas unit exergy costs are used as parameters for this purpose. In this chapter, thermo-economic objective function is defined as the unit total exergy cost per net power output of plants. Effect of design parameters of the gas turbine power plant on thermoeconomic performance is investigated and the results are discussed in Chapter 5 in ?Conclusions? section. The thermo-economic objective function for the optimization purpose is defined as the ratio of power plants net power output to total cost in all chapters. Numerical results are obtained by using FORTRAN programming language and the results are presented by graphics.