USING GENETIC ALGORITHMS AND THE EXERGONOMIC APPROACH TO OPTIMIZE DISTRICT-HEATING NETWORKS

This paper discusses the application of exergy analysis to a district heating network (DHN) currently in operation in Brescia (Italy). The p urpose is to compare the existing system design with that resulting fr om an exergonomic analysis. To this aim a general mathematical model i s formulated to account for irreversibilities due to the temperature a nd pressure losses as well as for the assessment of exergy exergy cost s for each stream. The objective function is stated as the sum of capi tal, operational, and maintenance costs of the whole DHN. Such a funct ion is minimized by using two different approaches: an iterative proce dure and a genetic algorithm; the latter proves To be particularly sui ted for this type of problem. Both methods lend to comparable outcomes in terms of minimum cost and plant arrangement. Finally, the optimum configuration is compared with the existing one and shows that the act ual network is far from an optimum design both from a thermodynamic an d an economic standpoint. Such a procedure could be used profitably in the design of any future DHN.