Synthesis and design of chilled water networks using mathematical optimization

This paper presents a mathematical optimization approach for the synthesis and design of chilled water networks. In this work, the main focus is given to efficient use of chilled water, with opportunities for reuse/recycle explored in order to lower the overall chilled water flow rate supplied to the network. Based on a superstructure that includes all possible network connections, mathematical models are developed for different integration schemes. Other than minimizing the chilled water requirement, a conflicting objective is included in the model to reduce network complexity and to improve flexibility. The design problems are formulated as mixed-integer nonlinear programming models. Two industrial case studies are used to illustrate the proposed approach. •A mathematical approach to chilled water network synthesis and design.•Direct and indirect integration using intermediate main(s).•Efficient use of chilled water for energy savings.•Case studies for Malaysian and Taiwanese wafer fabrication facilities.