Document Type : Original Article
Department of Mechanical Engineering, Aliabad Katoul Branch, Islamic Azad University, Aliabad Katoul, Iran
As any energy system produces functional products, such as work, heat, etc., it produces unintended remaining flows of matter or energy, too, which are called residues. One of the objectives of exergoeconomic analysis is to understand the cost formation process and the flow of costs in the system. In the conventional thermoeconomic methods, however, the problem of the cost of residues has not been perceived soundly. One of the complex problems in the cost assessment is residues cost allocation in a rational way. Two more important methods of the residues cost allocation are distribution of the cost of the residues proportionally to the exergy as well as to the entropy generation or negentropy. In this paper, a new method for the residues cost allocation is proposed. This new method uses the fuel-product (FP) table, a mathematical representation of the thermoeconomic model, as the input data. In order to represent the proposed method, a cogeneration system that produces 34MW of electricity and 18kg/s of saturated steam at 20bar is selected. For the optimization of this system, first, a code has been developed based on the real coding evolutionary algorithm and optimal solution is to be obtained; then, he proposed method is applied to the cogeneration system. For comparison of the results, two other methods have also been applied to the system. The results of the comparison show that the proposed method is more suitable and rational than the two other ones.