Bernier M A
Languages: English | Pages: 8 pp
Bibliographic info:
USA, Ashrae Transactions, Vol 103, Pt 1, 1997, preprint

This paper presents the results of a study aimed at quantifying the change in the U-factor caused by glass plate curvature in sealed, insulated glazing (JG) units. The curvature may be caused by a number of factors, two of which will be studied in this paper-barometric pressure and gas space temperature variations. In the first part of this paper, the equations governing glass plate deflections and heat transfer through JG units are briefly reviewed Then, glass plate deflections and the resulting change in the U-factor of several JG units are examined for ASHRAE-type winter conditions. Yearly simulations were also performed for Montreal, Canada, and Toulouse, France, to examine the combined effects of exterior temperature, barometric pressure, and wind speed These last results show that the U-factor of a particular JG unit (triple glazing, low-emissivity with air) may vary up to 5% above and 10% below the.yearly average.