This paper introduces a graphic tool for thermodynamic analysis to be used in energy analysis and integration of systems. The proposed tool, known as the energy-flow framework diagram (EFD), provides a new representation of an energy-flow scheme by nodes and node partners between utility buses and energy loss buses, based on the second law analysis, the exergy concept and dividing the object system into an energy target side and an auxiliary utility side. The paper presents the principles and features of the EFD and a series of restrictive criterions and revelatory criterions for using the EFD. The method was tested by application of a synthetic gas based 56 kt a(-1) one-step DME production process. The results provided a retrofitting process and proved the validity of the novel method. (c) 2006 Elsevier B.V. All rights reserved.