Experimental Validation of a COMSOL Multiphysics Model of Hygrothermal Transfer in a Bioclimatic Building with a Domed Roof

The building sector is one of the most energy-intensive and has the most impact on the environment, due to the use of cement for the manufacture of cinder blocks and concrete. Earth-based materials, thanks to their good thermal inertia, combined with a good choice of roof shape, such as domed roofs, are an alternative for reducing energy consumption and improving thermal comfort. To highlight the hygrothermal performance of earthen buildings with domed roofs, numerical modelling and simulation are used. Modeling is a tool that allows to predict physical phenomena in the building and the modeler must ensure the model's ability to predict them accurately before any simulation. The objective of this study is to experimentally validate a numerical model describing the hygrothermal transfers in an earthen building built with a hemispherical dome roof. The numerical model is implemented in the Comsol Multiphysics software. The meteorological data of the site, the air temperature, the relative humidity of the indoor environment and the temperatures of the interior and exterior surfaces of the building walls are measured. The data acquisition system consists of thermocouples, solarimeters and moisture meters, and this data is processed with Excel and Origin Pro software. Comparison of the simulated data and the measured data shows good agreement. The evaluation of the validation indicators shows that the NMBE values are between -5.63% and 0.3%, the CVRMSE between 0.75% and 7.42% and R2 between 76% and 96%. These values meet the limits recommended by ASHRAE Guideline 14 and show that the model can be used to reliably simulate internal and external thermal variations in the building while highlighting the effects of thermal inertia in the building walls. This research thus proposes a validated model that can be used in future parametric studies and for the optimization of the thermal performance of buildings.