WG3 Building physics and energy performance of structural skins
The building industry is moving towards zero energy buildings in Europe. Improving the envelope’s physical characteristics, developing surfaces with special properties and applying natural processes in the design of buildings are valuable strategies towards achieving this goal. Tensioned structures are competitive in this process due to their organic shape, minimum weight, high flexibility, translucency and low maintenance.
Topics such as the thermal and acoustic performance of structural skins and their use in controlling the internal comfort of buildings as well as energy harvesting will be assessed and investigated.
Single layered, multi-layered and adaptable membrane and foil structural skins are being used for permanent and semi-permanent building enclosures in diverse climates and for a wide range of functions. Increasingly these require a controlled internal environment, which necessitates enhanced thermal performance of the skin. Data does exist – in manufacturers’ data sheets for materials and in scientific papers on the environmental performance of enclosures – but is often incomplete and/or of limited application.
Tensile surface enclosures are unlike traditional forms of construction yet the predictive modelling of their thermal behaviour tends to be based on techniques developed for more conventional enclosures. A specific concern is the relative absence of experimental data from monitoring of the internal environment in tensile surface enclosures. Little is in the public domain. Without such data it is difficult to verify the accuracy of any analytical tool developed to predict the environmental performance.
The following aspects influence the overall environmental performance of enclosed spaces: the complex geometry, the relative importance of radiation as heat transfer mechanism, the absence of a steady state condition, the interaction with the external airflow and the possibility that the skin may be adaptable. Typical research topics are:
- The determination of accurate material properties pertinent to environmental design, e.g. acoustic, thermal insulation, translucency, vapour permeability, transmission of condensed water;
- Development of effective multi-layer systems using modified and coated materials for a variety of functions and climatic conditions, e.g. including thermal insulation;
- Designing multi-layer systems with advanced properties for harvesting solar energy (a) solar thermal energy for air and water heating, (b) flexible photovoltaic cells;
- The determination of the influence of factors relating to the thermal performance of the full enclosure;
- The detailed monitoring of existing enclosures in order to improve predictive modelling.