Optimal configuration design for plate heat exchangers Jorge A.W. Gut a , Jos  e M. Pinto a,b, * a Department of Chemical Engineering, University of S~ ao Paulo, Av. Prof. Luciano Gualberto, trav. 3, 380, S~ ao Paulo, SP 05508-900, Brazil b Othmer Department of Chemical and Biological Sciences and Engineering, Polytechnic University, Six Metrotech Center, Brooklyn, NY 11201, USA Received 1 November 2003; received in revised form 30 April 2004 Available online 20 July 2004 Abstract A screening method is presented for selecting optimal configurations for plate heat exchangers. The optimization problem is formulated as the minimization of the heat transfer area, subject to constraints on the number of channels, pressure drops, flow velocities and thermal effectiveness, as well as the exchanger thermal and hydraulic models. The configuration is defined by six parameters, which are as follows: number of channels, numbers of passes on each side, fluid locations, feed relative location and type of channel flow. The proposed method relies on a structured search procedure where the constraints are successively applied to eliminate infeasible and sub-optimal solutions. The method can be also used for enumerating the feasible region of the problem; thus any objective function can be used. Examples show that the screening method is able to successfully determine the set of optimal configurations with a very reduced number of exchanger evaluations. Approximately 5% of the pressure drop and velocity calculations and 1% of the thermal simulations are required when compared to an exhaustive enumeration procedure. An optimization example is presented with a detailed sensitivity analysis that illustrates the application and performance of the screening method. Ó 2004 Elsevier Ltd. All rights reserved. Keywords: Plate heat exchanger; Heat exchanger configuration; Optimization; Screening method 1. Introduction Gasketed plate heat exchangers (PHEs) are widely used in dairy and food processing plants, chemical industries, power plants and central cooling systems. They exhibit excellent heat transfer characteristics, which allows a very compact design, and can be easily dismounted for maintenance, cleaning or for modifying the heat transfer area by adding or removing plates. The PHE consists of a pack of thin corrugated metal plates with portholes for the passage of the fluids, as shown in Fig. 1. Each plate contains a bordering gasket, which seals the channels formed when the plate pack is com- pressed and mounted on a frame. The hot and cold fluids flow in alternate channels and the heat transfer takes place between adjacent channels. The corrugation of the plates promotes turbulence inside the channels and improves the mechanical strength of the plate pack [1,2]. Several flow patterns are possible for a PHE, depending on the exchanger configuration, which com- prises the number of channels, pass arrangement, type of channel flow and the location of the inlet and outlet connections on the frame. Because of the large number of possible configurations and the vast variety of com- mercial plates, the design of the PHE is highly special- ized. The PHE manufacturers developed exclusive design methods and, despite the large number of applications, rigorous design methods are not easily * Corresponding author. Address: Othmer Department of Chemical and Biological Sciences and Engineering, Polytechnic University, Six Metrotech Center, Brooklyn, NY 11201, USA. Tel.: +1-718-260-3569; fax: +1-718-260-3125. E-mail address: jpinto@poly.edu (J.M. Pinto). 0017-9310/$ - see front matter Ó 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.ijheatmasstransfer.2004.06.002 International Journal of Heat and Mass Transfer 47 (2004) 4833–4848 www.elsevier.com/locate/ijhmt