Energy performance of earthen building walls in the equatorial and tropical climates: a case study of Cameroon

Energy performance of earthen wall office buildings in equatorial and tropical climates is investigated using a Simulink model and EnergyPlus software. The main aim of this numerical simulation study is to quantify the magnitude of the effect of adding a fibrous material or a stabiliser in the compressed earth block on the energy requirement or thermal comfort of a building taking into account different operating modes of the cooling system (continuous, intermittent and no cooling) in some climatic conditions in Cameroon. For continuous air-conditioned space and intermittent air-conditioned space, the assessment parameters are cooling load and its peak, while it is thermal comfort index for no air-conditioned space. Thermophysical properties of the used earthen materials were previously measured. The results show that the mixing of sawdust or pozzolan with earth material improves its performances for continuously and intermittent cooling space case, and degrades it for non-air-conditioning space case. It can provide a reduction in peak sensible cooling rate by up to 6.3%, 7% and 10% in Yaoundé, Douala and Garoua, respectively. The thermal comfort index obtained with earth block wall can be smaller than that of earth block with 8% of sawdust wall by up to 10.41% and 13.03% (in August) in Yaoundé and Douala, respectively.