Industrial Energy Retrofit Planning Using Automated Retrofit Targeting

There is increasing pressure for industrial sites to minimise energy consumption. A long-term energy reduction strategy plays a critical role in realising energy savings. A key exchange mechanism of energy for sites is the heat exchanger network, which can be revamped and retrofitted to lift process energy efficiency. Retrofit analysis of heat exchanger networks commonly looks for a modified design that could provide significant energy savings for a comparatively modest investment but rarely does the analysis consider how retrofit projects can be sequenced as part of an energy retrofit plan while staying with capital investment constraints. The challenge in developing a long-term plan is the identification of projects and their ideal order out of the numerous possible combinations. This paper aims at developing an energy retrofit planning tool by performing a multi-stage retrofit analysis based on the automated retrofit targeting algorithm used to search for retrofit designs. The key output of the energy retrofit planning analysis is several sets of retrofit plans that can be further analysed for case-specific practicality (e.g., space, distance, and fluid compatibility) and developed into an energy retrofit plan, forming a part of a company’s overall energy strategy. The method is demonstrated using two industrial case studies with complex features and room for multiple sets of retrofit modifications. For the petrochemical complex case study, the study concludes that a 4-stage retrofit plan could be undertaken under a strategic investment plan that in total requires 11 modifications to the system, which generates 1.47 million EUR in annual profit with a payback of 1.75 years.