In this study, the gas turbine power plant with preheater is modeled and the simulation results are compared with one of the gas turbine power plants in Iran namely Yazd Gas Turbine. Moreover, multiobjective optimization has been performed to find the best design variables. The design parameters of the present study are selected as: air compressor pressure ratio (r AC ), compressor isentropic efficiency (Z AC ), gas turbine isentropic efficiency (Z GT ), combustion chamber inlet temperature (T 3 ) and gas turbine inlet temperature. In the optimization approach, the exergetic, economic and environmental aspects have been considered. In multiobjective optimization, the three objective functions, including the gas turbine exergy efficiency, total cost rate of the system production including cost rate of environmental impact and CO 2 emission, have been considered. The thermoenvironomic objective function is minimized while power plant exergy efficiency is maximized using a genetic algorithm. To have a good insight into this study, a sensitivity analysis of the results to the interest rate as well as fuel cost has been performed. In addition, the results showed that at the lower exergetic efficiency in which the weight of thermoenvironomic objective is higher, the sensitivity of the optimal solutions to the fuel cost is much higher than the location of Pareto Frontier with the lower weight of thermoenvironomic objective.

SUMMARY In this article, an integrated solid oxide fuel cell (SOFC) and micro gas turbine (MGT) with a multi‐effect desalination (MED) system is proposed, and its comprehensive thermodynamic modelling, through energy and exergy analyses, is conducted. In addition, the effects of some design parameters on the hybrid system are investigated. The results show that fuel cell stack pressure has a significant effect on the combined system power and distilled water capacity. It also increases the SOFC‐MGT energy efficiency. Moreover, the pressure of the inlet heating steam to the multieffect desalination system affects the pure water production in a positive way. An increase in the steam pressure results in a lower steam mass flow rate generated in the heat recovery steam generator. However, it increases desalination product capacity. Copyright © 2011 John Wiley & Sons, Ltd.

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In this article, analytical modeling of two-dimensional heat conduction in a hollow sphere is presented. The hollow sphere is subjected to time-dependent periodic boundary conditions at the inner and outer surfaces. The Duhamel theorem is employed to solve the problem where the periodic and time-dependent terms in the boundary conditions are considered. In the analysis, the thermophysical properties of the material are assumed to be isotropic and homogenous. Moreover, the effects of the temperature oscillation frequency, the thickness variation of the hollow sphere, and thermophysical properties of the sphere are studied. The temperature distribution obtained here contains two characteristics, the dimensionless amplitude (A) and the dimensionless phase difference (ϕ). Moreover, the obtained results are shown with respect to Biot and Fourier numbers. Comparison between the present results and the findings from a previous study for a hollow sphere subjected to the reference harmonic state show good agreement.