Theory of similarity and modelling. Similarity of phenomena. Basic criteria of similarity in the area of heat, mass and momentum transfer. Criterion equations. Dimensional analysis, p-theory, Huntley method. Method of converting equations into dimensionless form. Method of the similarity transformation. Modelling - types of models. Mathematical modelling, isomorphic equations. Hydrothermal, electro-thermal analogy. Physical modelling. Approximate modelling, partial and complete auto-similarity. Numerical modelling. 1D modelling of thermal systems. 3D models. Finite volume method. Finite element method. Methods for determining boundary conditions. Inverse problem of heat conduction. Examples of modelling of specific processes. Heat removal by cooling the hot surface with water nozzles. Heating and cooling of steel in a crucible furnace. Solidification and cooling of steel during continuous casting. Cooling material during heat treatment. Heat losses in distribution networks.