Environmental Parametric Multi-Objective Optimization to Design High Performance Façades using Daylight, Solar and CFD Analysis

A façade is the part of a building that forms the primary thermal barrier with its environment. It represents the most important factor for the determination of the level of thermal comfort, daylighting and ventilation and amount of energy required for the heating and cooling of the environment (Sacht et al., 2016). Jaali screens (perforated screens) as a façade system can reduce indoor glare, solar insolation, and facilitate cool breeze. The study is inspired from the working principles of ancient Jaali screens of South East Asia. By changing the depth, aperture, and shape of the cross-section of the Jaali modules, one can achieve indoor visual and thermal comfort. The study showcases an algorithmic approach to optimizing the façade screen for daylighting, solar insolation, and wind speed objectives.

Motivation for the study is derived from three aspects. First, the emphasis on simulation driven design as designs derived from intuition are often different from reality. Second, integration of CFD in Architectural, Engineering and Construction (AEC) industry. And third, questioning of the typical Multi-Objective Optimization (MOO) itself when designing for objectives with trade-offs. The study analyses the trade-offs between indoor daylight, solar radiation, and wind speed objectives and showcases two methods to optimize the façade screens for a test case building in New Delhi. The optimized façade screens using the typical MOO process and a new zoning strategy are then compared with the test case. The idea of the study is to showcase an improved Multi Objective Optimization (MOO) using zoning strategy approach to fully take advantage of all the objectives in the study.

The principles of these intricate and beautiful Jaali patterns could be expanded to the facades, glazing systems, and window systems of our modern buildings to enhance indoor environmental comfort and reduce building energy loads. The methodology to designing facades using a zoning strategy instead of the typical MOO strategy (of finding an optimal solution for the whole façade) could also be expanded to other building components.