A Pinch-Based Approach for the Synthesis of Chilled Water Network

This paper aims to address energy efficiency issue in the chilled water network (CHWN) system. Chilled water is a typical cooling agent used for heating, ventilating and air conditioning (HVAC) in various industrial, commercial and institutional facilities. In the conventional setup of CHWNs, chilled water is distributed throughout the buildings via piping connection to various HVAC heat exchangers in order to provide required air conditioning and equipment cooling. In this work, we attempt to address the problem from Process Integration perspective. The underlying principle of CHWN synthesis is to design the network in such a way that the chilled water is sent to the heat exchangers in a series fashion, rather than the conventional parallel arrangements. This enables the CHWN to be supplied with a lower flowrate of cooling water, which leads to less pumping work, and enables the chilled water return temperature to be maximized, thus increasing the chillers efficiency. A chilled water composite curve (CHWCC) is presented to determine the minimum chilled water flowrate needed for a CHWN. A network design algorithm is then used to design the CHWN to achieve the minimum chilled water flowrate. A hypothetical example is used to illustrate the newly proposed algorithm.