Thermoeconomic optimization of combined cycle gas turbine power plants using genetic algorithms Manuel Vald es * ,M a Dolores Dur an, Antonio Rovira Departamento de Ingenier  ıa Energ etica y Fluidomec  anica, Universidad Polit ecnica de Madrid, E.T.S. Ingenieros Industriales, Jos e Guti errez Abascal 2, 28006 Madrid, Spain Received 20 March 2003; accepted 13 June 2003 Abstract This paper shows a possible way to achieve a thermoeconomic optimization of combined cycle gas turbine (CCGT) power plants. The optimization has been done using a genetic algorithm, which has been tuned ap- plying it to a single pressure CCGT power plant. Once tuned, the optimization algorithm has been used to evaluate more complex plants, with two and three pressure levels in the heat recovery steam generator (HRSG). The variables considered for the optimization were the thermodynamic parameters that establish the con- figuration of the HRSG. Two different objective functions are proposed: one minimizes the cost of production per unit of output and the other maximizes the annual cash flow. The results obtained with both functions are compared in order to find the better optimization strategy. The results show that it is possible to find an optimum for every design parameter. This optimum depends on the selected optimization strategy. Ó 2003 Elsevier Ltd. All rights reserved. Keywords: Thermoeconomics; Combined cycle gas turbine; Heat recovery steam generator; Genetic algorithms 1. Introduction If the sole objective of a CCGT design was to maximize the thermodynamic efficiency, its total cost would be very high. This is why many authors [1–4] have made thermoeconomic studies in order to get a compromise between plant efficiency and generation costs. * Corresponding author. Fax: +34-1-3363006. E-mail addresses: mvaldes@etsii.upm.es (M. Vald es), mduran@enerflu.etsii.upm.es (M a .D. Dur an), rovira@mot- ores.etsii.upm.es (A. Rovira). 1359-4311/$ - see front matter Ó 2003 Elsevier Ltd. All rights reserved. doi:10.1016/S1359-4311(03)00203-5 Applied Thermal Engineering 23 (2003) 2169–2182 www.elsevier.com/locate/apthermeng