Transient hygrothermal behaviour of Lime-Hemp Materials
(2008)
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- Authors
- Supervisors
- De Herde, André
- Abstract
- (en) Energy use during human activities has an important impact on the environment. The building sector is responsible for one third of all primary energy used worldwide. Following sustainable development principles, energy and materials should be considered “from cradle to grave” to improve global performances of buildings. Lime-Hemp Materials (LHM) have numerous advantages: they have low embodied energy, they store CO2, they can be recycled, they adapt to new or old buildings, they give healthy environments… Based on literature and a thorough analysis of the “state of the art” of LHM use, the present work uses recent software WUFI® to quantify hygrothermal performances of LHM components under dynamic climates considering their transient behaviour. Classical assessment usually assumes permanent transfer and neglects the influence of sun, rain or wind. All hygrothermal parameters necessary to input LHM-wall (“wall” mixture) in the database of the software are measured and discussed. Thermal and hygric inertia are introduced through 2x2 combined parameters: diffusivity and effusivity. Seven different types of multi-layer components are then compared through WUFI® simulations. The influence of sun, rain and wind is analysed for the Belgian reference climate. Thermal and hygric inertia of those components are expressed through a new set of parameters characterizing their transient behaviour. LHM-wall components appear to have high thermal and hygric inertia. With this model, the yearly demand of energy predicted by the software (taking into account the influence of sun, rain, wind and transient effects) is similar to the results obtained with classical assessment. If new research is suggested, the present work demonstrates that, for equivalent components in term of thermal transport coefficient, components with high thermal and hygric inertia offer a higher comfort feeling in winter and in summer. The results of this work should be used to improve our knowledge regarding the transient behaviour of a wide range of other sustainable building components, and to optimize their performance in relation to the climate under which they are subjected
- Affiliations
Citations
Evrard, A. (2008). Transient hygrothermal behaviour of Lime-Hemp Materials. https://hdl.handle.net/2078.5/129307