Dynamic Shading Device

Responsive shading systems can dynamically improve indoor environmental conditions based on outdoor climate variations. Among the technologies, low-cost microprocessors and sensors associated with computational algorithms control the performance of pre-programmed tasks such as the opening, closing, and rotation of elements integrated into the façade. This paper presents the design, construction, and performance evaluation of a responsive brise-soleil constructed in Curitiba, PR, Brazil (Cfb, humid subtropical). This project is part of an ongoing Ph.D. thesis. The system is based on a small-scale model developed at Lyle Center for Regenerative Studies during the winter season in California, USA. The responsive device functionality considers luminous and thermal comfort parameters: Useful Daylight Illuminance and the Adaptive Comfort Model (ANSI/ASHRAE 55). This device adapts the regular use of a commercial brise-soleil louver and motorization system into upward and downward direction slat rotation regulating direct and diffuse solar radiation incidence. The window is subject to three shading patterns: 0% shade, 50% shade, and 100% shade. The responsive rules consider outdoor air temperature, indoor air temperature, globe temperature, operative temperature, neutral operative temperature, indoor illuminance at the work plane, and the current solar angle and azimuth. Preliminary results of the full-scale model applied on the façade of a Cost-effective Bioclimatic Building Chamber (CBBC) demonstrate the system's feasibility in controlling indoor air temperature and illuminance at the work plane. The performance evaluations considered two scenarios: statically and responsively shaded. The responsive device reduced the period when the operative temperature remained under the lower thermal comfort threshold and prevented overheating, reducing the demand for heating and cooling systems. The period when the illuminance level remained within the comfort level was proportional for both scenarios. However, the responsive system reduced the amount of time when the user would be subject to discomfort caused by glare. This responsive device concept is subject to further improvements and implementation on buildings, contributing to reducing energy demand during the operational phase for lighting, cooling, or heating. The design concept and functionality criteria might be interesting for dynamic façade developers.