Exergy and Environmental Analysis for Optimal Condition Finding of a New Combined Cycle

Abstract

In this paper, various thermal energy systems are studied to recover waste heat from gas turbines with different configurations. The exergy analysis and environmental examination are applied to achieve better insight into the suggested systems. Also, multi-objective optimization is employed to find the optimal condition of the introduced plants. In this work, various systems such as gas turbine (GT), organic Rankine cycle (ORC), and Kalina cycle (KC) with Proton Exchange Membrane (PEM) electrolyzer are combined to achieve a new system design. In this study, Engineering Equation Solver (V11.755) and Matlab (R2023a) software are used to simulate and optimize the proposed system. The comparison of systems shows that the combustion chamber with 3622 kW has the most considerable exergy destruction in the IGT/ORC-KC plant. The comparative investigation shows that IGT/ORC-KC has the highest output at 5659 kW, while the smallest exergy destruction is associated with the IGT system with 1779 kW. The multi-objective optimization considering three objective functions, namely, exergy efficiency, product cost, and environmental effects of exergy destruction, is conducted. Three-objective optimization on the IGT/ORC-KC unit shows that in the optimum point selected by the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) approach, the exergy efficiency, cost of product, and environmental effect of exergy destruction rate are 29.5%, 0.31 USD/kWh, and 13.22 mPt/s.