Combined conduction,convection,and radiation heat transfer model for double-glazed windows

Abstract

Window condensation in dwellings and offices can be very troublesome. Not only does it obstruct the view through the windows, but also runs off to accelerate the deterioration of paintwork, frames, and furniture. To evaluate and reduce the risk of condensation in buildings, analytical and numerical models have been developed to calculate the longitudinal temperature distribution of the indoor glazing. It is shown that the temperature variation is primarily due to buoyancy-driven gas flow within the sealed enclosure. However, the window edge seal and frame have a considerable effect on the temperature distribution and also on the U-value of the window. Measurements and a two-dimensional numerical solution have been used to ascertain the cold bridge effects of windows' edge seals and frames on the temperature distribution along the height of the inner glazing. This study takes into consideration all modes of heat transfer, i.e. convection, radiation, and conduction encountered at the bottom edge of the indoor glazing. The analysis provides a method for quantifying the condensation so common in the European and North American climates.

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