Investigation on heat and moisture transfer in bio-based building wall with consideration of the hysteresis effect

Abstract

Two mathematical models describing heat and moisture transfer in porous media were used to predict the hygrothermal behavior of a new type of bio-based materials made of date palm concrete (DPC). The finite element method was used for the resolution of partial differential equations and numerical results were compared to experimental data considering similar conditions of temperature and relative humidity through the DPC wall. At first, a mesh sensitivity analysis was carried out and the optimum mesh configuration was determined.Afterwards, the hysteresis effect was implemented in the models and its influence on the variation of the relative humidity through the wall was discussed. The results revealed that the proposed models globally provided satisfactory results for the DPC wall, with an improved accuracy when considering the hysteresis effect. Finally, a comparison in terms of thermal insulation and moisture buffering capacity between DPC and a classical building material was performed numerically. Results showed that the new bio-based wall is very promising and can contribute to mitigate temperature variation and ensure hydrothermal comfort in buildings.

Thermal and hygroscopic study of hemp concrete in real ambient conditions

“…This slight difference can be caused by the heterogeneity of the material, the uncertainty on the physical properties of the material during the characterization campaign, and the sensor's position and accuracy. Furthermore, the hysteresis effects also present a major factor of discrepancy [41], [42], [43], [44]. Fig.…”

Sensitivity analysis of transient heat and moisture transfer in a bio-based date palm concrete wall

“…A good agreement was reported between theoretical/experimental data for both temperature and RH profiles [13]. Recently, we carried out a detailed validation of Kunzel's model using COMSOL Multiphysics software in the case of a DPC wall, using the same setup and scenarios described in section 2.2 [12]. As an illustration, theoretical and experimental profiles obtained at a depth of 3cm in the DPC wall for temperature (scenario 1) and RH variations (scenario 2), are presented in Fig.…”

“…method [32]. The wall presented in section 2.2 was simulated and discretized following the same procedure as in [12]. A schematic view of the simulated wall and boundary conditions is presented in Fig.…”

“…In 1995, Kunzel [11] developed his own model based on a thorough investigation of heat and mass transport mechanisms in porous building materials. Since then, Kunzel's model has been widely used by researchers in the field of bio-based building materials, and has also been validated by comparison with experimental evidences in several works [12,13].…”

Dataset on the hygrothermal performance of a date palm concrete wall

“…6). Since the transfer is considered one dimensional through the thickness of the wall, mesh was generated following transfer direction where the wall was discretised into 100 layers [12]. Numerical results at 3 cm depth corresponding to scenarios 1 and 2 are presented respectively in Table 1, Table 2.…”