Exploring the potential of smart and multifunctional materials in adaptive opaque façade systems.

Abstract

Climate adaptive façades are considered promising breakthroughs for the reduction of energy consumption, as energy exchange is enabled when the weather conditions offer benefits instead of threats. So far, conventional building envelopes enhance thermal performance through opaque façade components and static insulations. Therefore, natural resources from the building environment remain untapped. Little research has been done in adaptive opaque façades, even if their dynamic behaviour shows a strong potential to exploit environmental resources. For the successful development of these innovative façade systems, a balance between sophistication and benefit is necessary. To manage this objective, the implementation of smart and multifunctional materials in the envelopes seems promising, as they are able to repeatedly and reversibly change some of its functions, features, or behaviour over time in response to environmental condition. Consequently, to trigger the response of the envelope, no external actuator or complex software management would be necessary. Nevertheless, these materials do not fulfil all of the façade requirements by themselves. Thus, they need to be combined with other adaptive technologies and building elements. This paper shows an initial definition of different façade configurations that include reactive materials, which enable the adaptiveness of opaque façade systems. The desired results are new façade roles suitable for a temperate climate, according to the potential of these multi-performance materials in the external layer of the envelope: the dynamic temperature change of the external cladding through the solar reflectance change and the enhancement or prevention of thermal losses through shape-changing ventilated façades. To achieve these new high performances, an ideal approach to the thermal behaviour of each façade layer was taken, and the required physical properties of each element was highlighted. As a result, we propose a mapping of a potentially suitable combination of reactive materials with other building elements that might enable holistic adaptive thermal performance.