CH-93-07-2 -- Heat Transfer at the Edge of Sealed Insulating Glass Units: Comparison of Hot Box Measurements with Finite-Difference Modeling

A number of new insulated spacer bars, which are intended to improve the thermal performance of the edge of sealed insulating glass units (IG), were recently introduced into the market. This technology focuses on an area of the glass that extends about 63mm above the sight line of the IG perimeter and is usually where a high condensation risk occurs. The insulated spacer bars help increase the surface temperatures on the room side of the window, therefore, the terminology "warm edge technology" (WET) has been introduced in the literature. Presents the results of a first step in evaluating the effect of WET features on the glass temperature in the edge-of-glass region of IG units. The thermal performance of different IG units made with spacer bars (which incorporate WET features) has been investigated by measurements in an environmental test facility and by calculations using a two-dimensional finite-difference heat transfer model. Measured surface temperature distributions and heat fluxes through the edge of glass are compared with the results from computer modelling.

KEYWORDS: heat flow, double glazing, performance, windows, heat loss, condensation, properties, thermal conductivity, thermal bridges, climate chambers, testing, calculating, surface temperature, temperature distribution, comparing, computers, thermocouples.

Units: SI