Nathaniel Huygen and John Sanders
Nathaniel Huygen, Research Associate, National Brick Research Center, 100 Clemson Research Blvd. Anderson, SC 29625, United States, nhuygen@clemson.edu
John Sanders, Director, National Brick Research Center, 100 Clemson Research Blvd. Anderson, SC 29625, United States, jpsand@clemson.edu
ABSTRACT
Wall systems that have significant thermal mass show reduced energy usage compared to lightweight walls with a similar thermal resistance. Utilizing a specialized hot box apparatus,
several wall systems were measured for both steady-state and dynamic thermal performance. Two types of wall systems were analyzed—the first consisted of a 2×6 steel-stud wall with various configurations of continuous insulation, batt insulation, and two different claddings—modular brick veneer or Exterior Insulation and Finish Systems (EIFS). The second type of wall consisted of an 8-inch lightweight concrete masonry unit (CMU), continuous insulation, and either modular brick veneer or EIFS cladding. A 24-hour day-night or “Sol-Air” cycle was imposed on the exterior of the assembly, and the total energy transfer through the wall measured. By utilizing a series of heat flux transducers in the hot box apparatus, localized performance in the zone of the steel-studs or CMU webs could be monitored during testing. Inclusion of modular brick veneer and an air cavity was found to improve the steady-state thermal resistance on average by 0.32 m2K/W and reduce the heat flow through the wall under the applied cycle by more than 30%. Experimental results were used to validate finite element modeling of these wall assemblies under steady-state and dynamic conditions. From these finite element models, the magnitude of the thermal bridging caused by the steel-studs could be quantitatively analyzed and a thermal framing factor calculated. Qualitative effects from thermal bridging of the steel-studs were obtained using an IR camera mounted within the metering chamber of the hot box apparatus.
KEYWORDS: brick veneer, dynamic thermal performance, hot box apparatus, finite element modeling, IR camera
