Optimized control strategy for Venetian blinds in an event space with fully glazed facades

Abstract

The present Master thesis explores the implementation of a glare-based control strategy for Venetian blinds in buildings with totally transparent facades. The case study concerns the Co-Creation Center, a building that hosts three different types of events: presentations, meetings and workshops. The diverse occupancy patterns, coupled with the four fully glazed facades, make the effective blinds control a challenging task to achieve using a traditional rule-based approach. Therefore, in this project, an optimized control system is proposed, aiming at the minimization of visual discomfort due to glare, as well as the minimization of energy demands for electric lighting by increasing daylight entry. The control strategy is developed within Grasshopper, a promising tool for parametric and optimization problems. Grasshopper allows for the creation of a parametric model that can be adjusted to other similar buildings with fully glazed facades by modifying the input parameters. Radial Basis Function Optimization (RBFOpt), a model-based optimization method performed by Grasshopper’s component Opossum, is utilized for the computation of the optimal blinds’ states. within the developed control strategy, Ecyl is used as a glare index, giving the opportunity to evaluate its performance. Results show that the developed algorithm can improve the existing visual conditions in the Co-Creation Center by an average of 80% for all activity types, although it led to an average increase of 7% in the time steps where electric lighting is needed, in comparison to the current control. Nevertheless, the time-consuming ray-tracing process performed by Grasshopper for each time step and the non-automated use of the RBFOpt component Opossum, slowed down the optimizations and made their use rather unsuitable for real-life implementation of the control strategy. Despite the impractical use of Opossum, RBFOpt was proved a promising optimization method. Finally, Ecyl displayed an overall agreement of 92.5% with DGP, proving that in spaces with multiple windows and uncertain occupants’ view direction, a view-independent index can predict glare risks adequately well, after being carefully correlated with another reliable view-dependent metric.