Temperature-dependency of hysteretic sorption in hygrothermal modelling of wood fibreboard sheathing: analysis of exterior wall laboratory experiments

Abstract

Wood is known for its temperature-dependent and hysteretic sorption behaviour. Several hysteresis models can be found from the literature, but the temperature-dependency of sorption especially in cold temperatures has received less attention. In this paper, we show experimental results for low-density fibreboard, which can be obtained with relatively inexpensive equipment and used for constructing temperature-dependent EMC function. The results were applied in the numerical analyses of a previous laboratory experiment involving an exterior wall with an LDF layer as sheathing. The optimal parameters for hysteresis models were determined by the least-squares data fitting approach. Our conclusion is that both the temperature-dependency and hysteresis in sorption behaviour must be included and with proper model parameters in the hygrothermal model in order to obtain satisfactory results when modelling LDF sheathing in a cold climate. Existing literature related to these aspects in hygrothermal modelling is scarce, and more experimental and computational research is needed.