Relating Bridge Analysis for Heat Exchanger Network Retrofit Identification to Retrofit Design

Abstract

The aim of the paper is to improve a recently developed automated HEN retrofit targeting method by linking the shapes of the Exchanger Shifted Composite Curve (ESCC) and Exchanger Grand Composite Curve (EGCC) to the required HEN retrofit design measures. The automated HEN retrofit targeting method is based on Bridge Analysis, which identifies new and existing utility paths for energy saving through the enhancement and/or addition of heat exchanger area and the installation of new exchangers. To build the required understanding, generic cases are analysed, one of which is presented. Links between the Exchanger Composite Curves with the required HEN retrofit design are established. The analysis concludes that the Heat Surplus-Deficit Cascade for some recovery exchangers may be divided two sections – Pinched and non-Pinched sections – to better represent and identify the number and type of modifications that a retrofit opportunity will require.