Entropy Generation Modelling (EGMod) is the topic dealing with the calculation of entropy sources in real processes. It is gaining ground since the entropy generation rate aggregates all irreversibility sources through a meaningful combination allowing to evaluate the energy-efficiency and sustainability of a given operation. Several EGMod approaches are reported in literature and are based on 1D process models or CFD simulations. 1D models are the most used given their computational efficiency, however, no study has compared their performances to CFD yet. In this paper, EGMod approaches are compared through three case studies highlighting their potentials and limitations. The results reveal that, although 1D approaches can correctly determine the temperature and concentration profiles along the process, they inherently lead to significant errors in the calculation of the entropy generation rate. These errors become important in the presence of chemical reactions as they lead to intercorrelation between local temperatures and concentrations.