Sharif Digital Repository

In the present study a comprehensive thermoeconomic modelling of a heat recovery steam generator (HRSG) for a typical 4MW class gas turbine is performed. Usually, the thermoeconomic analyses involve a thermodynamic model of the HRSG and an economic model dedicated to assess the cost. In this study, different configurations of single and dual pressure level HRSGs are optimized and afterward compared to find the economical design. For these configurations thermodynamic model calculates the performance and the energy balance of systems at the optimal operating conditions which are derived from optimization model, and economic model estimates total cost per unit of produced energy. Finally,... 

The supplementary firing is one of the techniques which are used to increase the output power of the combined cycle power plants (CCPP). The low construction cost per generated power encourages designers to consider it in the new CCPP. In this paper the thermal and exergy analyses of HRSG for various operating conditions in variation of loads and variation of ambient temperature carried out. They are based on the performance test data at different operating conditions. The objective of these analyses is to present the effects of supplementary firing on gross power output, combined cycle efficiency and the exergy loss in Heat Recovery Steam Generator (HRSG) devices at different ambient... 

The heat recovery steam generator (HRSG) is one of the few equipments that are custom made for combined cycle power plants, and any change in its design affects all performance parameters of a steam cycle directly. Thus providing an optimization tool to optimize its design parameters and the layout of its heat exchangers is of great importance. A new method is introduced for modeling a steam cycle in advanced combined cycles by organizing non-linear equations and their simultaneous solutions by use of the hybrid Newton methods in this article. Thereafter, optimal thermodynamic performance conditions for HRSGs are calculated with the help of the genetic algorithm. In the conclusion, the... 

This article addresses a combined approach of sliding mode control (SMC) with generalized predictive control (GPC) to achieve fluid temperature control in the evaporator of a heat recovery steam generator. The evaporator is modelled as a first-order plus dead time process. The model is developed using the experimental data obtained at an actual power plant. An output error identification algorithm is used to minimize the error between the model and the experiments in different operating conditions. A GPC method is exploited to optimize the sliding surface and the coefficients of the switching functions used in SMC. The proposed control schemes are evaluated by thorough simulation for... 

In this paper, an adaptive critic-based neurofuzzy controller is presented for water level regulation of nuclear steam generators. The problem has been of great concern for many years as the steam generator is a highly nonlinear system showing inverse response dynamics especially at low operating power levels. Fuzzy critic-based learning is a reinforcement learning method based on dynamic programming. The only information available for the critic agent is the system feedback which is interpreted as the last action the controller has performed in the previous state. The signal produced by the critic agent is used alongside the backpropagation of error algorithm to tune online conclusion parts...