A Tool for Thermoeconomic Analysis and Optimization of Gas, Steam and Combined Plants

Abstract

The aim of this work is to demonstrate the capability of an original “modular” simulator tool for the thermoeconomic analysis of thermal-energy systems. The approach employed is based on the Thermoeconomic Functional Analysis (T.F.A.) which, through definition of the “functional productive diagram“ and the establishment of the capital cost function of each component, allows the marginal costs and the unit product costs, i.e. the “internal economy“, of the functional exergy flows to be obtained in correspondence to the optimum point. The optimum design of the system is obtained utilizing a traditional optimization technique which includes both physical structure of the energy system described in terms of thermodynamic variables and cost model (capital cost of the components, maintenance and amortization factors, unit fuel cost, unit electricity cost, etc.). As an application example to show the practicability of the tool, the thermoeconomic analysis of various complex multi-pressure combined cycles (with or without steam reheating) is carried out. The results are analyzed and discussed in depth.