CH-03-09-2 (RP-1145) -- Modeling Transient Performance of Two-Dimensional and Three-Dimensional Building Assemblies PDF

Most building envelopes have thermal bridging: locations where the thermal resistance of the assembly is compromised for structural or framing reasons. While some transient calculation programs account for the reduced thermal resistance, few programs account for the transient thermal effects of the thermal bridging. This paper describes a simplified model, referred to as “the equivalent wall method,” which is intended to simplify the analysis and improve the accuracy of modeling three-dimensional effects. The equivalent wall model involves creating a fictitious multi-layer wall with properties selected so that its dynamic response to the transient conditions is very close to that of the real wall with two- and three-dimensional effects.

Units: Dual