22 Int. J. Exergy, Vol. 18, No. 1, 2015 Copyright © 2015 Inderscience Enterprises Ltd. Developing of constructal theory concept for plate-fin heat exchanger modelling, design and optimisation Amir Farhang Sotoodeh* and Majid Amidpour Faculty of Mechanical Engineering, Department of Energy System Engineering, K.N. Toosi University of Technology, Tehran 19991-43344, Iran Fax: 0098 21 8867 4748 Email: af_sotoodeh@dena.kntu.ac.ir Email: amidpour@kntu.ac.ir *Corresponding author Mehrangiz Ghazi Department of Mechanical Engineering, Takestan Branch, Islamic Azad University, Takestan 1477893855, Iran Email: M.Ghazi@tiau.ac.ir Abstract: In this paper, the modelling, design and optimisation of plate-fin heat exchangers has been carried out by applying the concept of constructal theory. Current heat exchangers design method call for use of one scale flow structure but constructal plate-fin heat exchanger is designed by multiple length scales with more than one construct. The objective function is to investigate the geometries that give best heat recovery or higher cold stream outlet terminal temperature. The design parameters include number of constructs and geometric variables of each construct. The constructal heat exchanger volume and heat transfer area are kept constant and equal to the volume and heat transfer area of the optimised ordinary heat exchanger. The potential applicability and effectiveness of the current methodology is demonstrated on a case study. The optimisation of the case study reveals higher heat recovery in constructal plate-fin heat exchanger in comparison with ordinary plate-fin heat exchanger. Keywords: constructal theory; plate-fin heat exchanger; heat recovery; pressure drop; multimodal genetic algorithm. Reference to this paper should be made as follows: Sotoodeh, A.F., Amidpour, M. and Ghazi, M. (2015) ‘Developing of constructal theory concept for plate-fin heat exchanger modelling, design and optimisation’, Int. J. Exergy, Vol. 18, No. 1, pp.22–45. Biographical notes: Amir Farhang Sotoodeh has studied BS, MSc and PhD in Mechanical Engineering in K.N. Toosi University of Technology. He is the Member of Scientific Board of NRI in Iran. His favourite topics are constructal