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Heat flux along the diagonal of a unit cell for a pillar separation of 20 mm, glass sheets of 3 mm and 7 mm thickness, and a 10 mm thick buffer plate with different values of resistance

Heat flux along the diagonal of a unit cell for a pillar separation of 20 mm, glass sheets of 3 mm and 7 mm thickness, and a 10 mm thick buffer plate with different values of resistance

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This is the second of two papers concerning errors in the measurement of the thermal insulating properties of Vacuum Insulating Glass (VIG) due to non-uniformities in the heat flow due to the support pillars. Part 1 deals with the situation where the measurement area is in direct thermal contact with the glass sheets. This paper discusses how the n...

Citations

... Given the above, the precise determination of internal pressure in the cavity is critical for the design of IGUs. This may be related to the possible loss of integrity of an IGU due to secondary sealing failure or premature glass failure caused by the combination of high mechanical stresses in glass resulting from high internal pressure and thermal stresses, which may be superimposed in certain areas [12]. Experiments, analytical and numerical studies on the performance of flat IGUs have been the subject of many studies [13][14][15][16][17][18][19][20][21][22][23] and engineering approaches were included in standards (eg [24]). ...
Article
The application of curved glass provides exceptional freedom in the design of modern wavy shapes of building enclosures. The stiffness resulting from curvature has been identified as a remarkable advantage over flat glass, decreasing support requirements, and improving esthetics or increasing spans. However, many constraints arise regarding its design, manufacture, and performance during operation. Due to improved stiffness, curved Insulating Glass Units (IGUs) have a limited ability to equalize internal and atmospheric pressure changes by pillowing, compared to flat IGUs. High internal pressure values may lead to visible visual distortions or failure of the secondary seal. This paper presents the results of experiments, Finite Element (FE) and analytical simulations of flat and cylindrically curved insulating glass units. The study involved seven IGU specimens with 4 mm component panes and a 16 mm cavity. All specimens had a constant width (500 mm) but differed in length (500, 1000 and 1500 mm), and arc radius (two radii of curvature were used, 1500 and 2500 mm). In this study, the main focus was on the influence of geometric parameters on internal pressure in the cavity. The study uses a rarely used technique to simulate varying pressures in the IGU cavity by injecting or withdrawing of a defined volume of gas into/from the cavity.
... Due to improved stiffness, curved IGUs cannot equalise internal and atmospheric pressure changes by pillowing, as flat IGUs do. Therefore, the climatic loads in curved IGUs can be several times higher compared to flat units, leading to glass fracture or failure of the silicone seal, particularly in combination with mechanical stresses [3]. ...