An insulated wall can be supported internally by thin steel studs. There will be extra heat loss caused by the metal U-studs, but slitting the web of the U-studs perpendicular to the heat flow direction reduces this heat loss. Calculation of the heat transmittance is a difficult numerical problem due to the high ratio of thermal conductivity between the insulation and the steel. This study presents results of calculations in three dimensions. The proper choice of the numerical mesh is discussed. Simplified equations for the U-factor are derived and implemented in a computer program. The heat transmittance is quickly calculated for different parameters-thermal conductivity of insulation and steel, steel thickness, distance between studs, and additional insulated layers (with or without cross-laid steel studs). A few results from hot box measurements are also presented.

AUTHOR: Thomas R. Blomberg, D.Sc., Johan Claesson, Ph.D.
CITATION: Thermal Performance of the Exterior Envelopes of Buildings VII
KEYWORDS: December, Florida, 1998
YEAR: 1998