Impact of insulation and wall thickness in compressed earth buildings in hot and dry tropical regions

• Published in: Journal of Building Engineering 2021-01, Vol.33, p.101612, Article 101612
• Main Authors: Neya, Ibrahim, Yamegueu, Daniel, Coulibaly, Yézouma, Messan, Adamah, Ouedraogo, Arnaud Louis Sountong-Noma
• Format: Article
• Language: English
• Subjects: Energy model; Engineering Sciences; Experimental validation; Thermal behaviour; Thermal comfort; Tropical climate
• ISSN: 2352-7102; 2352-7102
• DOI: 10.1016/j.jobe.2020.101612

Outdoor climatic conditions such as sun radiation, air temperature and humidity, wind speed are the main factors that determine the thermal response of free-running buildings. However, the thermal behaviour of buildings can be regulated by a proper choice of suitable materials to maintain thermal comfort for the occupants. Through a validated energy model, this article evaluates the influence of insulation and thermal mass on the envelope of a compressed stabilised earth blocks test cell in a hot and dry tropical climate. The study assesses the impact of these parameters on building thermal performance. The effect of insulation is studied by considering different insulators made of glass wool or straw mixed with lime. The thermal inertia impact has been assessed by varying the wall thickness. The results show that insulation with 0.10 m glass wool thickness and 0.15 m straw mixed with 0.02 m lime have very close thermal performance. The study also shows that the appropriate wall thickness for adequate thermal comfort depends on the building insulation state. Without insulation, the wall thicknesses of 0.22 m and 0.35 m showed the best thermal performance. The corresponding decrement factors were respectively 30% and 17%. An insulated wall thickness of 0.14 m was the optimal choice because this choice lowered outdoor temperature amplitude to 22% and was more resource efficient. •Thermal inertia effects in free-running buildings in hot and dry climatic regions.•Assessment of thermal inertia effects through an empirical validation approach.•Comparison of the convention insulator glass wool with an ecological one, the straw.•Assessment of thermal mass influence on decrement factor and time lag.•Thermal mass and insulation greatly influence the building indoor environment.