Non-Pareto optimal solutions as enablers for versatile heat exchanger networks

Abstract

Assessing a heat exchanger network (HEN) based on total annual costs (TAC) alone is no longer appropriate. Climate-damaging emissions must also be considered. Thus, we use CO2 emissions and TAC as objectives in the fully linearized heat exchanger network synthesis (HENS). Due to uncertainties concerning emissions and equipment costs, a refurbishment of the HEN may become necessary even before its life cycle has been reached. Since a significant share of the system costs is related to the piping, it is economical to change only the heat exchanger (HEX) areas. To assess the potential for the refurbishment of a given HEN in the future, we constrain the Pareto optimal HEN configurations and recompute sub-Pareto fronts. Our results show that there are obviously superior configurations regarding distance and coverage of the sub-Pareto front concerning the initial Pareto front. The hypervolume indicator (HVI) and the coverage were used as quantitative indicators to evaluate different configurations. However, these characteristic parameters do not correlate with empirically determined high-quality configurations. This contribution has laid an essential foundation towards developing versatile and optimal HEN.