The paper presents a new general criterion equation for calculating heat transfer under conditions of natural convection of the hydrocarbon and non-hydrocarbon media with local deposit formation on the heat exchange surface. Information sources on the research topic were analyzed. Examples of deposits in certain power plants and jet engines are provided. Main factors influencing the carbon-containing deposits on the heated walls of the fuel and coolant supply channels are considered. The new equation for calculating heat transfer was obtained based on a new deposit formation similarity criterion created by the author of this article, which simultaneously takes into account both the thermal and electrochemical nature of this process. Values of the new electrochemical numbers used in the calculation and included in the deposit formation similarity criterion were found for the carbon-containing deposits in the kerosene media and for the salt deposits (NaCl salt). Results of the experimental studies were generalized in the TS-1 kerosene media, salt solution and air with local deposit formation on the heat exchange surface. Some generalization results are presented in the corresponding graphs.