Thermo-economic Analysis of Power Cycles

Exergy analysis is based on combined first and second laws of thermodynamics and is a useful tool to analyze the energy systems in a better and more realistic way than an energy analysis, based on the first law of thermodynamics. Combination of exergy from thermodynamics with conventional concepts from engineering economy which is referred to as thermo-economy (exergo-economy) is a valuable tool to analyze the energy systems in a better way. In this paper, efforts are made to apply the concept of thermo-economy to analyze two power cycles (a combined Gas and Steam cycle and a conventional steam power plant). In this analysis, the results of an exergy calculation are combined with the economic aspects such as investment costs, fuel costs, and also operation and maintenance costs. The goal of this study is to show how to implement the concept of thermo-economy to these cycles and also how to estimate the price of the product (electric power generated). Assessment of the components exergy destruction costs is a second objective in this study. Results obtained from this analysis clearly show the effect of the cost breakdown and the component performance on the price of the final product. Comparison of the price of the product in these cycles shows that the combined cycle is superior to the conventional steam power plant.