Parameter estimation and model selection for water sorption in a wood fibre material

Abstract

The sorption curve is an essential feature for the modelling of heat and mass transfer in porous building materials. Several models have been proposed in the literature to represent the amount of moisture content in the material according to the water activity (or capillary pressure) level. These models are based on analytical expressions and few parameters that need to be estimated by inverse analysis. This article investigates the reliability of eight models through the accuracy of the estimated parameters. For this, experimental data for a wood fibre material are generated with special attention to the stop criterion to capture long time kinetic constants. Among five sets of measurements, the best estimate is computed. The reliability of the models is then discussed. After proving the theoretical identifiability of the unknown parameters for each model, the primary identifiability is analysed. It evaluates whether the parameters influence on the model output is sufficient to proceed the parameter estimation with accuracy. For this, a continuous derivative-based approach is adopted. Seven models have a low primary identifiability for at least one parameter. Indeed, when estimating the unknown parameters using the experimental observations, the parameters with low primary identifiability exhibit large uncertainties. Finally, an Approximation Bayesian Computation algorithm is used to simultaneously select the best model and estimate the parameters that best represent the experimental data. The thermodynamic and Feng-Xing models, together with a proposed model in this work, were the best ones selected by this algorithm.

On the importance of desiccant during the determination of water vapor permeability of permeable insulation material

“…Nevertheless, it is strongly hygroscopic as shown in Fig. 1 [25]. Furthermore, product datasheet indicates a water vapor diffusion resistance factor of 2.…”

Numerical and experimental estimation of building wall heat flux in presence of moisture transfer

“…The investigated wall is a classical wood frame wall, including rainscreen membrane, medium density fiberboard (MDF), wood fiber insulation (WFI) and OSB sheathing (see figure 1). The materials hygrothermal properties presented in table 1 are taken from materials database or measured in lab for WFI [18][19][20]. The theoretical U-value calculated following by the standard ISO 6946 [1] is 0.14 W.m -2 .K -1 .…”

An efficient two-dimensional heat transfer model for building envelopes

“…The outside boundary conditions are modeled in two dimensions, i.e., varying according to the time t and the height y . To evaluate the influence of such modeling on the assessment of the energy efficiency of the facade, a derivative-based sensitivity analysis is carried out [20][21][22][23]. The four essential parameters in modeling the outside boundary conditions are the height of the front building F , the distance of the front building D , the first-order coefficient h 11 and the coefficient β of the power law described in Eq.…”