Moisture Buffering of Multilayer Internal Wall Assemblies at the Micro Scale: Experimental Study and Numerical Modelling

Abstract

In this paper, a series of experiments assessing the moisture buffer value (MBV) of four internal wall assembly samples made from hygroscopic materials was performed. A modified Nordtest protocol was used. Moisture buffer values of all the investigated wall assemblies, with varying moisture loads in the range of 50% to 80%, showed a moderate moisture buffer value (MBV: 0.5–1.0 (g·m−2·%RH−1)). The results showed that in a wall assembly where the MBV of the whole assembly is lower than the MBV of the outer layers, the moisture-buffering capacity of the inner layer is untapped. Outer layers affect inner layers by changing their moisture-buffering capacity, which in turn changes the overall performance of the whole assembly. In addition, it was observed that if the penetration depth value of the outer layer is greater than its thickness, vapour reaches into the deeper layer and wall assemblies made of layers with materials characterized by a lower value of penetration depth reach steady state more slowly. The WUFI Pro tool was used to compare the simulated and experimental results. Despite the discrepancies between these results, it offers a simplified method, helping designers make decisions about which materials to choose to improve the moisture-buffering effect.

A Discussion on Winter Indoor Hygrothermal Conditions and Hygroscopic Behaviour of Plasters in Southern Europe

“…Finally, similar differences between measured and simulated water content in building materials, during alternated cycles of high and low humidity, were also observed in previous studies [65][66][67].…”

Air Enthalpy as an IAQ Indicator in Hot and Humid Environment—Experimental Evaluation

“…The relationship between indoor air humidity and the humidity of the partitions and walls that are not discussed in this publication have been presented and discussed by Kaczorek [35] and Energies 2020, 13, 1481 5 of 21 Krause [36,37]. Air humidity also has a significant impact on the building's energy consumption, which was, for example, discussed by Gawin [38].…”

Energy Efficiency in Buildings and Innovative Materials for Building Construction

“…The evolution of the thermal and moisture profiles with time suggests that the adsorption of water vapor occurs together with the redistribution of liquid water within the envelope. Dobrosława Kaczorek, in her paper [12], conducted various experiments on the moisture buffering capacity of a series of walls assembled with hygroscopic materials. The research confirmed some results of previous work, in which it was suggested that there is a mutual influence of one layer on the other, indicating that the multilayer walls have a hygric behavior difficult to assess.…”