A general theory for boiling heat transfer could be developed in the future, if the heat transfer of a single bubble and the interaction between the neighbouring bubbles are integrated in the evaluation modeling. The influence of microstructure of a heating surface and of the bubble formation on nucleate boiling heat transfer is investigated. The aim is to develop a correlation of the local and temporal activation of the potential nucleation sites, which can be statistically determined by the envelope area method based on the roughness measurements of the heating surface before the heat transfer measurements. The activation of nucleation...