Assessment of hygrothermal behavior and energy efficiency of a compressed earth block building envelope

This study offers a comprehensive evaluation of the energy and hygrothermal performance of compressed earth block (CEB) building envelopes through a combination of experimental characterization and multiscale numerical modeling. At the material level, the thermal and hygric properties of CEB were experimentally measured and used as input parameters in a coupled heat and moisture transfer model based on Künzel's formulation. Validation was performed at the laboratory wall scale, showing close agreement between simulated and measured temperature and moisture profiles across wall depths. At the building level, thermal performance was assessed under representative Oceanic and Mediterranean climates in France. Simulations were conducted for a 98 m 3 office space occupied by two adults, comparing CEB wall assemblies to a traditional concrete envelope. Results show that CEB walls reduce heating demand by 15% under oceanic conditions and by 13% under Mediterranean conditions. Additionally, cooling demand is reduced by up to 75%, especially in Mediterranean climates. These improvements are mainly due to the higher thermal inertia and lower thermal conductivity of CEB materials. Dynamic analysis indicates increased time lag and decreased decrement factors, reflecting better attenuation of external thermal fluctuations. Hygrothermal results also demonstrate improved moisture-buffering capacity, less moisture buildup, and a lower risk of mold growth compared to concrete. This leads to more stable indoor conditions and enhanced thermal comfort. Overall, the findings emphasize the potential of CEB as a low-energy, high-performance building envelope suitable for various climatic conditions.