A new low-temperature hermetic composite edge seal for the fabrication of triple vacuum glazing

High performance low-cost vacuum glazing is a key development in the move to more energy-efficient buildings. This study reports the results of experimental and theoretical investigations into the development of a new low-temperature (less than 200 C) composite edge seal. A prototype triple vacuum glazing of dimensions 300mmx300 mm was fabricated with a measured vacuum pressure of 4.8 10 2 Pa achieved. A three-dimensional finite-element model for this prototype triple vacuum glazing with the composite edge seal was also developed. Centre-of-pane and total thermal transmittance values for this small prototype of the triple vacuum glazing were predicted to be 0.33 Wm 2 K 1 and 1.05 Wm 2 K 1 , respectively. It was predicted using the developed model that the thermal performance could be improved by reducing the width of the composite edge seal and by the use of soft lowemissivity coatings on the glass surfaces. Detailed three-dimensional isothermal contour plots of the modelled triple vacuum glazing are presented.