4EMulti-objective Optimization of Cogeneration Plant with Details Modeling of Recuperator

Abstract

There are many works on improving the performance of a cogeneration plant such as the implementation of a recuperator. In previous works, the authors modelled a gas turbine cycle considering the recuperator as a black box. In this paper, a cogeneration plant is modeled and optimized with details of recuperator parameters. For this purpose, 13 design variables for a plant as well as a recuperator are selected. Then, a genetic algorithm is applied to optimize exergy efficiency and total cost rate, simultaneously. This work included Energy, Economy, and Environmental factors which with Exergy provided 4E analysis. A 36% decrease in total cost and a 33% increase in exergy efficiency in comparison with a simple gas turbine system were found. The above results for a gas turbine with a preheater and inlet cooling system reveal a 36% decrease in total cost and 35% increases in exergy efficiency. In addition, the optimum recuperator design parameters reveal that, higher effectiveness is more important than the investment cost. Moreover, a plant with higher exergy efficiency needs a recuperator with a lower pressure drop. Finally sensitivity analysis for variation of objectives functions with a change in fuel cost and interest rate are performed.