The paper deals with simulation of the heat exchanger and model evaluation. There are presented partial differential equations of heat exchanger model, which assume liquid mediums. Presented, in the paper, model is used as an approximation for three different type heat exchangers. The purpose of these investigations was to explain weather the same model could match well to different of shape and type exchangers by adjusting some model parameters. There is shown a method of determining model parameters. Results of simulation are compared with measured data.