Limits to performance of evacuated glazing

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:194863

Turner, G M; Collins, R E; Fischer-Cripps, A C; Tang, J Z ^[1]

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1. Univ. of Sydney, New South Wales (Australia). School of Physics

This paper discusses the performance limitations of evacuated glazing. Evacuated glazing up to at least 1 m{sup 2} in area can be rapidly evacuated. The mechanical tensile stresses in evacuated glazing are strongly dependent on the level of insulation achieved, particularly with respect to the pillar array during manufacture. Highly insulating evacuated glazing contains stresses, in regions which can lead to fracture, that are comparable with conventional double glazing. It appears likely that such glazing can withstand temperature differentials of at least 40 C. Evacuated glazing consisting of two 1 m{sup 2} sheets of 4 mm thick glass, with internal pyrolytically deposited low emittance coatings, has been manufactured with an air-to-air mid device thermal conductance of approximately 0.85 Wm{sup {minus}2}K{sup {minus}1}, of which approximately 2/3 is due to radiation and 1/3 to pillar conductance. These samples have negligible gas conductance and an extremely stable internal vacuum at room temperature. Substantially lower values of radiative heat flow would require sputtered transparent low emittance coatings that can withstand the high temperature currently used in the solder glass edge sealing process. Lower pillar conductance can only be achieved using thicker glass sheets, or tempered glass.

• OSTI ID: 194863
• Report Number(s): CONF-9404167--; ISBN 0-8194-1564-2
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
DOUBLE GLAZING
OPTICAL PROPERTIES
PERFORMANCE
SEALS
SERVICE LIFE
THERMAL CONDUCTIVITY
THERMAL INSULATION
WINDOWS