Intersection | Performance-based Passive facade

Following the previous parametric forming, this work presents a performance-based approach to enhancing the passive design of a high-rise hotel facade in Turin through parametric optimization. It focuses on the transition from performance-driven form optimization to facade engineering. 

This main passive strategy combines external louvers and overhangs in a zigzag configuration to balance solar control, energy performance, and visual and thermal comfort. A parametric workflow in Grasshopper was developed to generate 48 southern facade variations, each evaluated through simulations using KPIs such as solar radiation reduction, ASE, sDA, and heating, cooling, and lighting EUI. The results were then compared using parallel coordinate charts to identify the most balanced design solutions. 

Performance-based design Methodology

A performance-based design methodology was developed through parametric modeling in Grasshopper to generate multiple design alternatives. These alternatives were evaluated using a set of key performance indicators (KPIs) for building physics performance. A total of 48 design variations were generated, of which three were identified as optimal solutions corresponding to different building orientations. 

One of the most interesting findings was that the best-performing facade was (unfortunately) not the one that blocked the most solar radiation in summer. The longest shading devices reduced summer solar radiation by up to 48%, but they also blocked beneficial winter solar gains, resulting in only about 12% annual energy savings. This revealed a key limitation of the proposed facade concept: while it performed well in summer, it was less effective in balancing solar gains across seasons, reducing its overall performance in Turin's temperate climate.

The study also showed that horizontal overhangs significantly improved daylight comfort by significantly reducing ASE while maintaining a perfect sDA of around 97%. However, none of the 48 configurations could reduce ASE below the target for the south-facing corner rooms, indicating the need for further solutions such as integrated shading blinds or advanced Tvis glass configurations. 

Three "optimal" variations and their parallel coordinates paths