Mathematical modeling of regime-dependent thermal response in multilayer wall assemblies with equal total steady thermal resistance

Steady thermal resistance is a fundamental characteristic of building-envelope assemblies; however, equal steady resistance does not uniquely determine their transient thermal behavior. This study aims to numerically separate the effects of layer order, temperature-dependent thermophysical properties, and redistribution of thermal resistance between bulk and interfacial components in stationarily equivalent multilayer wall assemblies subjected to periodic and finite-pulse thermal loading. A one-dimensional transient heat-conduction model with Robin boundary conditions, finite interfacial thermal resistance, and source-supported temperature-dependent material properties was employed. All compared configurations were constrained to the same total steady thermal resistance at the reference temperature, R t o t = 3.65315 m 2 K\/W. The numerical implementation passed the adopted verification procedure with restrictions. The combined grid/time uncertainty was 0.325 %, below the prescribed 0.5 % acceptance criterion. For the tested pair differing only in layer order, the relative effect was –0.905 % for the periodic decrement factor and +0.566 % for the finite-pulse peak transmission ratio, with effect-to-uncertainty ratios of 79.2 and 88.9, respectively; the opposite signs therefore refer to two distinct regime-specific metrics. The temperature-dependent configuration produced a numerically resolved periodic effect of –2.005 %, whereas the corresponding pulse effect of –0.282 % remained below the adopted numerical-resolution threshold. For a compensated 5-10 % redistribution of bulk thermal resistance to interfacial contacts, the additional dynamic effect was likewise unresolved. The results demonstrate the value of controlled factor separation combined with explicit numerical-uncertainty assessment when evaluating transient thermal behavior.