Abstract
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.
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Abbreviations
- c :
-
specific heat capacity (J kg−1 K−1)
- h :
-
combined heat transfer coefficient (W m−2 K−1)
- L :
-
wall thickness (m)
- q i :
-
heat flux density at indoor surface of the wall (W m−2)
- t :
-
time (s)
- T :
-
temperature (°C)
- x :
-
coordinate direction normal to wall (m)
- α:
-
solar absorptivity of outside surface of wall
- λ:
-
thermal conductivity (Wm−1 K−1)
- ρ:
-
density of material (kg m−3)
- i:
-
inside
- o:
-
outside
- sa:
-
solar-air
- t:
-
total
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The authors would like to acknowledge the Department of National Meteorology of Cameroon for providing the long-term dry bulk air temperature data.
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Highlights
• Thermal performance of earthen walls incorporating fibrous material or a stabiliser was studied.
• The study was carried out using H-Tools (the library of Simulink models) and EnergyPlus simulation programmes.
• The addition of sawdust or pozzolan in the compressed stabilised earth block showed better performance.
• An earthen wall configuration presented better performance than conventional wall.
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Wati, E., Bidoung, J.C., Damfeu, J.C. et al. Energy performance of earthen building walls in the equatorial and tropical climates: a case study of Cameroon. Energy Efficiency 13, 735–750 (2020). https://doi.org/10.1007/s12053-020-09856-6
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DOI: https://doi.org/10.1007/s12053-020-09856-6