How is finite element computer thermal modeling used?
In the early ’80s finite element computer modeling was developed to predict thermal performance of untested frame-glass combinations on custom systems. Thanks to the efforts of the National Fenestration Ratings Council, Lawrence Berkeley National Laboratories (LBNL) and the Department of Energy, this software is now publicly available and is widely used for system design. Many manufacturers, test labs and glass fabricators have modeling capabilities in-house. The key is “system” design: Glass manufacturers calculate and publish “center-of-glass” U-Factors inferred from the basic physics of solar-optical properties. For insulating glass, these represent the expected properties of two, infinite size lites of glass separated by an air space of given width. Of course, in the real physical world, thermal conductance of insulating glass edge spacers and framing can detract from the center-of-glass value. Modeling software like LBNL’s THERM program takes these complex edge effects into accoun
