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Summary: The major intention of this study is to reduce the total expenditure of a vapor absorption cooling system (VACS) by developing an optimization model with an alternative working pair LiCl‐H2O and compares it with the traditional LiBr‐H2O system. Considering the cooling capacity of 50 kW, two working pairs were to compare parametrically at various operating conditions. The model comprises of three parts, viz. a thermodynamic model for the estimation of coefficient of performance, exergetic efficiency, and availability destruction of system components; an economic model for computing expenditure flow rate and capital investing expenditure rate; and the minimization of the total expenditure using genetic algorithm. The parametric study suggests that a LiCl‐H2O system performs better from both thermodynamic and expenditure‐effective aspects under all working conditions involved in this study. Especially, a low generator temperature produces a noticeable difference. The present global optimization technique assesses the optimal operating temperatures of generator, absorber, condenser, and evaporator. An optimal operating condition provides a system with a 1.20% of decrement in total expenditure rate and 5.39% of reduction in total capital investing expenditure rate using LiCl‐H2O solutions with respect to LiBr‐H2O solutions. Finally, results derived from this study may assist to designers to choose an alternative working fluid for enhancing the performance of VACS. [ABSTRACT FROM AUTHOR]

Cost analysis has a significant importance to obtain the optimum marketing price of the product of thermal systems to maximize the benefit and/or minimize the cost. Thus, this paper focuses on the investigation of the magnitude of the change in costs with respect to load and environmental temperature variations. To achieve the objective, a useful and simple second law based thermo-economic model with instant access to production costs is introduced and generalized. The presented exergy costing method indicates that the cost of reversible power is the theoretically minimum cost, where the reversible power is the theoretical maximum power that can be gained from a thermal system. The analysis has been applied to a combined cycle power plant, which is located in Bursa/Turkey. The effects of load and environmental temperature variations on costs are discussed and presented. Without considering the load effect, the cost of net electric power varied from 29 to 32$ MW-1 h-1, and about 40–45% of the cost of net electric power is composed of cost of irreversibility, while its 55–60% of it is the cost of reversible power. It is shown that the augmentation in the costs are not continuous with the environmental temperature decrease. In addition, there is an extremum at the temperature range between 5 and 10°C. Copyright © 2006 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]