Hint: An educational software for heat exchanger network design with the pinch method A ´ ngel Martı ´n *, Fidel A. Mato Department of Chemical Engineering and Environmental Technology, University of Valladolid, Facultad de Ciencias, Prado de la Magdalena s/n, 47011 Valladolid, Spain 1. Introduction The cost of energy has increased dramatically in the last years, and this trend can be expected to continue. Additionally, there is a growing social concern about the sustainability of current industrial development. In this context, the ability to optimise the use of resources and in particular of energy is becoming an extremely important skill for chemical engineers. Two different methodologies have been successfully applied to minimize the use of energy in chemical processes. With the first one, the Heat Exchanger Network Synthesis (HENS) problem is formulated as a mixed integer non-linear optimi- sation problem (MINLP) (Biegler et al., 1997). The main advantage of this method is its capacity to find the best possible solution for the HENS problem. However, this method provides very limited information about the factors that determine the minimum energy consumption of a process, and about the possibilities to modify the process to reduce this minimum. The second methodology is the so-called pinch method, which is based on a thermodynamic analysis of the process (Linnhoff and Hindmarsh, 1983; Smith, 2005). The core elements of this method are the calculation of energy and cost targets for the process, which inform the minimum energy consumption and the minimum cost of the HEN required to reach this minimum, and a systematic methodology for the design of a HEN that actually meets those targets is based on the use of simplified graphical representations of the thermodynamic analysis. The pinch design method offers no guarantee of finding the optimal solution. However, it allows a HEN to be developed that operates with the minimum energy consumption and at the same time is a good approximation of the optimal network. Furthermore, it gives full control of the design to the engineer, and helps to identify the parameters of the process that are limiting the energy savings. For these reasons, the pinch design method is a popular and well-established tool for HEN design. The calculations required by pinch methodology are conceptually simple and can be done by hand. However, in real-scale problems they can become tedious and time consuming. Thus, the availability of a computer software that performs those repetitive tasks is of interest for the learning and application of the pinch method. Several education for chemical engineers 3 (2008) e 6– e 14 article info Article history: Received 20 April 2007 Accepted 17 August 2007 Keywords: Heat integration Pinch technology Freeware educational software Heat exchanger network Retrofitting analysis abstract A free piece of educational software for heat exchanger network design based on the pinch method is presented. The interface of the program has been designed focusing on getting a clear presentation of the concepts of the pinch design methods and letting students the control of all the stages of the design. The program guides students through all the main steps of the design, including energy and cost targeting, utilities selection, heat exchanger network specification, and optimisation and retrofitting analysis. The program has been tested in a MSc pinch technology course for several years, and the feedback obtained from students during this period has been used to optimise the program functionality and its interface. The use of the program improves the efficiency of the course since it let students practice the concepts of the pinch method while relieving them of tedious repetitive calculations. # 2007 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved. * Corresponding author. Tel.: +34 983423013; fax: +34 983423166. E-mail address: mamaan@iq.uva.es (A ´ .Martı´n). Abbreviations: GCC, Grand Composite Curves; GUI, Graphical User Interface; HEN, heat exchanger network; HENS, Heat Exchanger Network Synthesis; MINLP, Mixed Integer Non-Linear Programming. available at www.sciencedirect.com journal homepage: www.elsevier.com/locate/ece 1749-7728/$ – see front matter # 2007 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved. doi:10.1016/j.ece.2007.08.001