Some comments to the paper “Energy, exergy and sustainability analyses of hybrid renewable energy based hydrogen and electricity production and storage systems: Modeling and case study”

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.