The complex phenomenon of fouling when heating water solutions can significantly hamper the performance of heat exchangers. The fouling process is considered in an application for a plate heat exchanger (PHE) with enhanced heat transfer that proved to have much lower fouling tendencies than conventional shell and tube heat exchangers. To eliminate the drawbacks of the dimensional fouling model forms the dimensionless its form is developed. It is based on the equation for transport and chemical reaction fouling mechanism initially proposed for other types of fouling media. Thermo hydraulic mathematical model of PHE under fouling conditions accounting for the distribution of local process parameters along heat transfer surface is presented. It enables to predict not only thermal performance of PHE, but also pressure losses. The mathematical model consists of the system of differential equations with the nonlinear right-hand side. Its solution is implemented with software for the personal computer. The model application is demonstrated with two practical examples. It confirms models' validity and its acceptable accuracy for practical calculations of PHE in industry and also the possibility of proposed dimensionless model application for different fouling substances with the similar types of fouling mechanism. (C) 2019 Elsevier Ltd. All rights reserved.