A novel approach for synthesis of cost-optimal heat exchanger networks

This study presents a new hybrid methodology for synthesis of cost-optimal heat exchanger networks (HENs). The problem is solved in a two-level approach. The upper level generates the structure of HENs using harmony search (HS) algorithm. To evaluate the minimum cost of each structure, it is sent to the lower level in which the heat load of units and stream-split fractions are optimized by a combination of the HS and sequential quadratic programming (SQP). Based on the cost obtained for each structure HS ranks the HENs and produces new structures until algorithm converges to optimal solution. For validation purpose, three benchmark problems are examined and also a real-world industrial-sized problem is solved to demonstrate the applicability of this method for large-sized problems. The results of this study show that the new approach is able to find more economical networks than those generated by other methods.