This master thesis deals with the influence of the dew on the cooling effect of green building structures. In addition to the condensation of water vapor on vegetation of a green roof, we also analysed condensation of of water vapor in the night time on dedicated dew condensers. In the thesis we used two methods of calculating dew amount. We set up an empirical model and created a numerical model in Excel software environment and checked their adequacy in predicting the amount of condensed moisture with in-situ experiments. Afterwards, we carried out a numerical analysis of the amount of dew for places with different climatic characteristics, mainly using a numerical model, that proved to be more adequate. Results from the measurement showed, that the amount of dew condensed in a single night never exceeded 0,2 mm m-2 day-1, both on the green roof and on the dedicated collector, which represents only 1/3 of the theoretically possible amount according to the literature. Numerical analysis showed, that the annual amount of condensed moisture on the green roof in Ljubljana is 11,3 mm m-2 year-1, which represents only 1 % of the annual precipitation. Approximately the same share, 1 %, was also calculated for Berlin and Barcelona. The calculated amount of condensed moisture thus has no visible effect on the cooling effect of green roofs or the reduction of the required amount of water for irrigating the vegetation.
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