Numerical and Experimental Evaluation of the Drying Behaviour of Medium Density Expanded Cork Boards used as an External Coating

Abstract

The promotion of more efficient and greener buildings and the reduction of energy consumption are among the priorities defined in the Europe 2020 Strategy. The potential of incorporating different types of waste and by-products in construction materials and solutions is relevant for achieving a more sustainable construction and use of buildings throughout their life cycle. Example of this, is the use of the medium density insulation cork board (MD ICB) as an external insulation coating material. It is a fully natural and recyclable insulation material, made from the exudation of cork granules, a sub-product from the cork industry. This material is sensitive to rain conditions as it absorbs water. When the energy performance of buildings is being assessed, the influence of moisture on its thermal behaviour should not be neglected. A building's heat loss estimation can be far from reality if the materials' moisture content is not considered. Therefore, it is of crucial importance to evaluate the drying behaviour of MD ICB after wetting this material. A numerical simulation, using WUFI 2D 3.0 was performed to evaluate the materials' moisture content over time. In order to perform this study a thorough experimental characterisation of the material, in terms of hygrothermal parameters, was required. To validate the numerical model, the obtained numerical results were compared with experimental ones, in which MD ICB boards were dried in a climatic chamber, after being saturated with water. After the first 9 hours of drying, during which the moisture movement is mostly due to gravity, the experimental and numerical results present relatively good correlation.

Sustainability Improvement in the Design of Lightweight Roofs: A New Prototype of Hybrid Steel and Wood Purlins

“…The same sector is also responsible for the consumption of 30% of the world's resources and 12% of existing water resources, besides producing between 30-40% of the residues that end up in the landfill. Many of the actions in this sector concentrate on the use of materials with higher sustainable rates, in the broadest sense; in other words, materials that are recyclable, reusable, or naturally renewable, as in the case of wood-based materials [3][4][5][6][7][8]. The switch over to certain materials takes time and may not be globally achieved, although the process continues its gradual development, despite powerful lobbying against any disruption to industrial production.…”