Hygrothermal performance of hemp lime concrete embedded with phase change materials for buildings

The use of biobased materials in building construction allows the reduction of fossil resource use and energy consumption. Among biobased materials, hemp lime concrete has been investigated in many studies highlighting its capacity to regulate interior relative humidity and its high insulation capacity. In order to design high-performance biobased concretes, a new hemp lime concrete combining the hygric regulation capacity of hemp lime concrete with the thermal regulation performance of phase change material was developed. This article focuses on the thermal and hygric performance of the new hemp lime concretes incorporating micro-capsulated phase change material (PCM) (named HL-PCM). Three hemp lime concretes that differ from formulation were developed and investigated. The thermal properties, moisture buffer values and its impact on interior relative humidity variation have been presented. Thanks to experimental works and numerical simulations, the results obtained showed that the thermal conductivity remain low, the heat capacity and thermal inertia increase considerably for hemp concrete with PCM, while the moisture buffering capacity remains excellent. Finally, numerical results showed that the used of hemp lime concrete (with and without PCM) reduce indoor relative humidity variation and improve indoor hygrothermal comfort.