A visual basic application for Microsoft (R) Excel 2007 has been developed as a helpful tool to perform mass, energy, exergy and thermoeconomic (MHBT) calculations during the systematic analysis of energy processes simulated with Aspen Plus (R). The application reads an Excel workbook containing three sheets with the matter, work and heat streams results of an Aspen Plus (R) simulation. The required information from the Aspen Plus (R) simulation and the algorithm/calculations of the application are described and applied to an Air Separation Unit (ASU). This application helps the designer when MHBT analyses are performed, as it increases the knowledge of the process simulated with Aspen Plus (R). It's a valuable tool not only because of the calculations performed, but also because it creates a new Excel workbook where the results and the formulae written on the cells are fully visible and editable. There is free access to the application and it has no protection allowing changes and improvements to be done. (C) 2010 Elsevier Ltd. All rights reserved.