counterAKT

Abstract

To lessen our influence on the environment, we are moving towards solutions that can meet our needs of shelter, nutrition, mobility, communication, and health with little to no energy or resources. In the construction industry, adaptive façades have gained attention for their capacity to adapt to changing conditions. These façades can modify their state in response to varying factors such as temperature and sunlight. This adaptability offers potential benefits in energy efficiency and occupant comfort, making them significant in architectural advancement. Despite being promising, these technologies are seldom used in buildings because they consist of numerous components and intricate mechanisms that can hinder their overall lifespan. To find more straightforward solutions for these systems, designers and researchers have focused on Smart Materials in combination with passive strategies. Shape Memory Alloys (SMAs), in particular, have found applications in diverse designs owing to their dual functionality as temperature sensors and actuators. SMAs have the remarkable ability to ‘remember’ their original shape and can revert to it when subjected to specific temperatures. This unique trait enables them to serve as both sensors, by detecting temperature changes, and actuators, by initiating shape changes in response to those shifts. However, current SMA-based sunshade designs do not provide visual contact with the exterior, as they continuously block the occupant’s field of view. This work aims at lowering the mechanical complexity of SMA-based sunshades while maintaining thermal comfort and visual contact with the exterior. The first part highlights the significance of precise control strategies for effective sunshade designs. The research emphasizes the importance of tailored control methods aligned with climate conditions. The conclusion underscores that an optimal sunshade design must balance cooling demand reduction, thermal comfort maintenance, and opening hours. Mechanical designs should minimize components while ensuring maximal stroke capabilities. The mechanical design of the counterAKT system exhibited promising stroke results despite not reaching the 200% benchmark. Further research avenues are suggested for textiles and Shape Memory Alloys (SMAs). Integration of findings from both materials is essential for realizing a complete working counterAKT system. Nodal thermal modeling provided insights into the major factors influencing SMA temperature in the counterAKT system. Solar radiation and convective heat transfer were identified as key contributors. The conclusion recommends future research to shift reliance from outdoor air temperature to solar radiation by enhancing emissivity, reducing convection losses, and concentrating solar radiation on the SMA. Finally, The system’s feasibility is demonstrated through a small-scale prototype, affirming its practical viability and potential applicability.