A multi-plant heat exchanger network (HEN) can recover waste heat across plant boundaries and reduce utility consumption in industrial parks. Conventional multi-plant heat integration using nominal conditions cannot handle uncertainties from the environment or plant operations that affect stream properties; therefore, a flexible HEN design is more practical. This study is focused on the evaluation of an already designed flexible HEN with a fixed network structure and the provided heat exchanger areas to maintain operability under disturbances. Although the capital cost is determined, utility consumption is uncertain to meet possible target temperatures. Consequently, the total annual cost (TAC) varies and forms a distribution that can give plant operators more information about possible costs as well as extreme parameter values. To provide the TAC distribution, a mathematical model is established to calculate utility costs after inputting different stream parameters into the designed HEN configuration. In addition, an interval Shapley value from the fuzzy game, which considers the contribution of each plant when the decision environment is uncertain, is used to generate a cost allocation interval. For example, the potential costs paid for Plant 1 and Plant 2 in Case study 1 ranged from $18,195.95 to $25,897.80 and $14,778.05 to $19,921.20, respectively. These results demonstrate that the proposed approach can be used to evaluate a provided flexible HEN design before construction.
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