External shading in buildings: comparative analysis of daylighting performance in static and kinetic operation scenarios

Climate-adaptive building envelopes have been receiving increasing interest in recent years. The growing interest can be explained, among other reasons, by the technological advances in control and motion mechanisms and the increasing awareness of building performance and its influence on energy consumption and climate change. Dynamic external shades are one of the earliest examples of climate-adaptive building envelopes. Dynamic exterior shades can potentially optimize the internal illuminance and solar radiation over the building’s façade in relation to the sun’s position. They can also react to disturbances in the sun’s radiation, such as clouds, trees, adjacent buildings, and other urban elements, allowing dynamic adaptation of internal environmental conditions. However, the dynamic operation of louvers also has some limitations. Rapid, automatic movements of louvers can be disturbing. On the other hand, manual changes in louver orientation are highly dependent on the mindfulness of the occupants, who have been reported to be inconsistent at remembering to change the louver’s position, thereby affecting the building’s performance. According to research, people do not operate shades as much as is required to achieve optimal results. Their operation is done weekly or even monthly at most, aiming to improve the visual environment rather than the thermal. Although there is extensive scientific literature about the influence of static and dynamic external shades on internal illuminance and energy consumption, there seems to be a lacuna in the knowledge regarding the contribution of dynamic shading operation scenarios in relation to traditional static shading.

The research was developed in two stages. The first stage defined types of autonomous movement strategies, compared the advantages of these strategies over those of traditional methods of centrally controlled movement; and developed design experiments with physical prototypes that examined the potential of the implementation of the suggested approach using state-of-the-practice technology.

The second part of the first stage of the research developed a computational methodology and tool that could parametrically examine possible decentralized control and operation mechanisms and compare the efficiency of the two control methods in dealing with environmental conditions such as natural light distribution.