The topic of this paper is thermodynamic calculation of heat exchange and checking and proving whether the heat exchanger is possible in the selected configuration, and checking and proving that temperature crossings occur, and if so, determine in what quantity and choose a solution to reduce or eliminate the occurrence of temperature intersections. The introductory (theoretical part) explains the main concepts of heat exchangers, recuperative type Shell and Tube Heat Exchangers, performance, divisions, exchanger applications as well as the principle and mode of operation. Then an explanation of all the relations used in the experimental part of the paper is presented, the relations for the preliminary calculation as well as for the extended calculation are treated separately. In the experimental part, a preliminary calculation based on the "Kern" method is performed first and then an extended calculation is performed using the "Bell Delaware" and "Shell number" methods, all for the selected heat exchanger configuration, Shell and tube, E type, counter current configurations. All calculations will be made in the Engineering Equation Solver (EES) software. At the end of this paper an analysis, the results obtained by the preliminary and extended calculation are compared and argued. And on the basis of the obtained geometric data from the extended calculation, the heat exchanger itself was constructed