An algorithm for the steady-state simulation of a plate heat exchanger is presented, which takes into account a general unit with n flow channels, in which the hot and cold streams may flow co- or countercurrently, according to any of the possible flow patterns: series or parallel flow, with either single or multipass arrangements. The temperature profiles are calculated using the numerical method originally proposed by T, Zaleski. K. Klepacka [J. Mass Heat Transfer 35 (5) (1992) 1125]. which approximates the solution for each channel by a linear combination of exponential functions. In order to validate the developed algorithm, simulation results were compared with exact analytical solutions available for simple cases and experimental data. Once validated. the algorithm was successfully utilised to simulate the steady-state operation of an industrial plate heat exchanger used for pasteurising milk. (C) 2002 Elsevier Science Ltd. All rights reserved.