Exergoeconomic optimization of a diesel-engine-powered cogeneration plant

An iterative exergoeconomic optimization procedure is applied to an actual diesel-engine-powered cogeneration plant. The method is based on the cost-optimal exergetic efficiency that is obtained for a component isolated from the remaining system components. Objective functions that express the optimization criterion for each subcomponent of the cogeneration system are developed. Product exergy flow rates and specific fuel exergetic costs of each subcomponent are kept constant as constraints. In the iterative optimization procedure, the variables, relative cost difference, and exergetic efficiency with the corresponding optimal values are obtained. Exergoeconomically optimal values for total cost flow rate, cost of electricity, and cost of steam are determined to be US $2316/h, $0.0670/kW h, and $0.0450/kg, respectively, whereas the corresponding actual base case values are US $2932/h, $0.0890/kW h, and $0.0522/kg, respectively.