In the course of this master thesis an Excel-program for dimensioning of packed columns for direct-gas-cooling, caused by condensation and evaporation was compiled. This program is based on the idea, to calculate the heat transfer coefficient with the established model of Schultes, instead of working with empirical values. Furthermore an additional aim is to apply the HTU-NTU-Model to calculate the height of pile in a column. The first part of this thesis deals with the backgrounds, which are important for the compiled program. In the second part all calculation steps for both types of columns are explicated by the means of two examples.