Quantifying potential dynamic façade energy savings in early design using constrained optimization: Fid-Bau Portal

Quantifying potential dynamic façade energy savings in early design using constrained optimization

Hinkle, Laura E. / Wang, Julian / Brown, Nathan C.

Abstract Parametric design and optimization studies have demonstrated high energy savings for dynamic building envelope materials compared to static high-performance envelopes. However, most parametric studies about dynamic buildings were conducted on prototypical buildings with a focus on either optimal geometric settings or idealized material property characteristics, neglecting the potential collective effects of geometric and material design decisions on energy performance. This study investigates the implications of an automated sequential optimization process while designing with dynamic envelope materials. Two case studies were used to quantify energy savings across different optimization-based design procedures and identify the relative importance of various decision categories. When considering realistic design constraints and intrinsic material limitations, geometric optimization alone yielded only 2% energy savings, while dynamic material optimization savings reached up to 19%. Significantly, a sequential design process in which the geometry is configured first before the façade is optimized and vice versa can lead to around 5% missed energy savings. These findings encourage changes to traditional design guidelines and simulation-based building design approaches when working with dynamic façades.

Highlights • Optimizing facade materials yields more energy savings than optimizing geometry. • Sequential optimization for facade geometry and materials can reduce energy savings. • Of individual design variables, window-to-wall ratio has most effect on energy use. • Yet with daylight requirements, altering material properties enables lower energy.