A cost targeting method for studying investment on heat exchanger network for collection of industrial excess heat

Paper in proceeding, 2015

This paper discusses the design of water based heat collection system for recovery of industrial excess heat. The focus in on the problem of finding the optimal combinations of excess heat sources minimizing heat exchanger network capital costs for different amounts of total recovered heat. A cost targeting approach based on vertical heat transfer between hot process streams and the heat collection medium in Pinch Analysis diagrams is used. The set of process streams where heat shall be recovered is found by solving an optimization problem where heat recovery is maximized while minimizing the capital costs simultaneously. A genetic algorithm based optimization tool is used. The analysis is conducted for three plants belonging to a chemical cluster. The results are compared with results from previous investigations in which the process excess heat sources were chosen based on their incremental heat contribution. The new approach presented in this work allows identifying a much larger set of solutions as well as considerably lower capital costs for similar amount of recovered heat in cases when process streams largely differ in terms of temperature levels and heat transfer properties.