Energy Performance of Evacuated Glazings in Residential Buildings

TitleEnergy Performance of Evacuated Glazings in Residential Buildings
Publication TypeConference Paper
Year of Publication1996
AuthorsRobert Sullivan, Fredric A Beck, Dariush K Arasteh, Stephen E Selkowitz
Conference NameASHRAE 1996 Summer Meeting, June 22-26, 1996
Date Published06/1996
Conference LocationSan Antonio, TX
Other NumbersUC-1600

This paper presents the results of a study investigating the energy performance of evacuated glazings or glazings which maintain a vacuum between two panes of glass. Their performance is measured by comparing results to prototype highly insulated superwindows as well as a more conventional insulating glass unit with a low-E coating and argon gas fill. We used the DOE-2.1E energy analysis simulation program to analyze the annual and hourly heating energy use due to the windows of a prototypical single-story house located in Madison, Wisconsin. Cooling energy performance was also investigated. Our results show that for highly insulating windows, the solar heat gain coefficient is as important as the windows U-factor in determining heating performance for window orientations facing west-south-east. For other orientations in which there is not much direct solar radiation, the windows U-factor primarily governs performance. The vacuum glazings had lower heating requirements than the superwindows for most window orientations. The conventional low-E window outperformed the superwindows for southwest-south-southeast orientations. These performance differences are directly related to the solar heat gain coefficients of the various windows analyzed. The cooling performance of the windows was inversely related to the heating performance. The low solar heat gain coefficients of the superwindows resulted in the best cooling performance. However, we were able to mitigate the cooling differences of the windows by using an interior shading device that reduced the amount of solar gain.

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