The Potential of Bridge Analysis in Heat Exchanger Network Retrofit

Abstract

Improving energy efficiency in the industrial sector remains a top priority in efforts towards guaranteeing a sustainable economy and safe environment. Energy integration is a crucial solution for reducing fuel consumption and coping with growing energy crises. As a part of this approach, industries are seeking specific ways to reduce their energy consumption. For example, methods and techniques for improving the energy performance of a heat exchanger network (HEN) have been successfully developed to enhance heat recovery and reduce utility demands. This research project aimed to explore the potential of the bridge analysis (BA) of HEN design methodology and compare its effectiveness with the network pinch (NP) and simulated annealing (SA) methods. Two HEN case studies were adopted to implement these methods. In this research, the results of all three methods were differentiated regarding the amount of energy savings compared to the capital cost spent on the retrofitting process. All three methods accomplished the maximum energy savings for both case studies, but there were notable differences. Both BA and NP provided an almost similar number of topology modifications to achieve the maximum energy savings. Interestingly, the total modification area of the BA retrofit was significantly lower compared to the NP and SA results. This greatly impacted the annualised capital cost of the modifications. A conclusion that can be drawn from this study is that BA can be considered an efficient retrofit method that provides considerable insight into energy-saving modifications. However, the evaluation of BA has shown that retrofitting an existing HEN may necessitate much time and effort due to the need to manually evaluate various potential retrofit design options after they have been generated by the spreadsheet tool (an automated heat surplus-deficit table, or HSDT). The BA method has made notable progress in the literature; however, there is still room for development and further success that can help in the exploration of the economic potential for retrofitting an existing HEN.