Optimum design of dual pressure heat recovery steam generator using non-dimensional parameters based on thermodynamic and thermoeconomic approaches Sanaz Naemi a , Majid Saffar-Avval a, * , Sahand Behboodi Kalhori b , Zohreh Mansoori c a Mechanical Engineering Department, Amirkabir University of Technology, Hafez Ave., P.O. Box 15875-4413, Tehran, Iran b Lab. for Alternative Energy Conversion, Mechatronic Systems Engineering, School of Engineering Science, Simon Faser University, Canada c Energy research center, Amirkabir University of Technology, Iran highlights < Presenting thermodynamic and thermoeconomic optimization of a heat recovery steam generator. < Defining an objective function consists of exergy waste and exergy destruction. < Defining an objective function including capital cost and cost of irreversibilities. < Obtaining the optimized operating parameters of a dual pressure heat recovery boiler. < Computing the optimum pinch point using non-dimensional operating parameters. article info Article history: Received 14 May 2012 Accepted 6 December 2012 Available online 21 December 2012 Keywords: Heat recovery steam generator Exergy analysis Optimum pinch point temperature Thermoeconomic analysis abstract The thermodynamic and thermoeconomic analyses are investigated to achieve the optimum operating parameters of a dual pressure heat recovery steam generator (HRSG), coupled with a heavy duty gas turbine. In this regard, the thermodynamic objective function including the exergy waste and the exergy destruction, is defined in such a way to find the optimum pinch point, and consequently to minimize the objective function by using non-dimensional operating parameters. The results indicated that, the optimum pinch point from thermodynamic viewpoint is 2.5  C and 2.1  C for HRSGs with live steam at 75 bar and 90 bar respectively. Since thermodynamic analysis is not able to consider economic factors, another objective function including annualized installation cost and annual cost of irreversibilities is proposed. To find the irreversibility cost, electricity price and also fuel price are considered indepen- dently. The optimum pinch point from thermoeconomic viewpoint on basis of electricity price is 20.6  C (75 bar) and 19.2  C (90 bar), whereas according to the fuel price it is 25.4  C and 23.7  C. Finally, an extensive sensitivity analysis is performed to compare optimum pinch point for different electricity and fuel prices. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction Due to global energy crisis, an increasingly attitude to efficient energy conversion technologies especially Combined Cycle Power Plants (CCPPs) have seen in recent decades, in which gas turbine operating in open cycle is integrated with a steam cycle by means of a Heat Recovery Steam Generator (HRSG). Hereupon, HRSG provides the critical connection between the gas turbine topping cycle and the steam turbine bottoming cycle. Undoubtedly, the optimum design of HRSG has a particular interest to improve the perfor- mance of heat recovery for maximizing the power generated by steam cycle. Besides, it reduces the environmental impacts of pollutant emissions. In the design of HRSGs, the method to obtain the optimum design usually is a combination of the thermody- namic and economic point of views. The exergy method, which uses the conservation of mass and energy principles together with the second law of the thermodynamics, is a useful tool to identify the locations, types and magnitudes of losses. In the past decade, coupled energy and exergy analyses of different thermal systems have been carried out. Dincer and Rosen * Corresponding author. Tel.: þ98 21 66405844; þ98 21 66419736. E-mail addresses: sanaz_n@aut.ac.ir (S. Naemi), mavval@aut.ac.ir (M. Saffar- Avval), sbehbood@sfu.ca (S. Behboodi Kalhori), z.mansoori@aut.ac.ir (Z. Mansoori). Contents lists available at SciVerse ScienceDirect Applied Thermal Engineering journal homepage: www.elsevier.com/locate/apthermeng 1359-4311/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.applthermaleng.2012.12.004 Applied Thermal Engineering 52 (2013) 371e384