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,... 

Domed roofs have been used in Iran and many other countries to cover large buildings such as mosques, shrines, churches, schools, etc. However their favorable thermal performance made them to be employed in other buildings such as bazaars, or market places, in Iran. The aim of this study was to determine the air pressure distribution over domed roofs, employing a numerical method. In this investigation, a three-dimensional model and a laminar inlet air flow were considered. The k-ε RNG method was employed for the turbulent flow simulation method. Simulation was run under three conditions of windows and a hole on top of the dome being open, or closed. The results were compared with the... 

Boiling of water/triethyleneglycol (TEG) binary solution has a wide-ranging application in the gas processing engineering. Design, operation and optimization of the involved boilers require accurate prediction of boiling heat transfer coefficient between surface and solution. In this investigation, nucleate pool boiling heat transfer coefficient has been experimentally measured on a horizontal rod heater in water/TEG binary solutions in a wide range of concentrations and heat fluxes under ambient condition. The present experimental data are correlated using major existing correlations. In addition a correlation is presented for prediction of pool boiling heat transfer for the system in which... 

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...