Energy Efficient Shape Optimization of Building Facades in Severe Continental Climates

The optimization of facade shapes for transient heat transfer management in building enclosures remains an underexplored area, particularly in extreme climates such as Astana city in Kazakhstan. This gap is largely due to the numerical complexity involved in shape optimization under transient thermal conditions. This study aims to tackle this challenge by enhancing the energy efficiency of building facades in Astana city by optimizing outside shape of the wall using an implicit method. A two-dimensional transient heat diffusion model is employed to simulate the thermal behavior of the facade, incorporating convective and short-wave solar radiation effects through a third-type boundary condition. The interior surface is governed by a Robin boundary condition. To efficiently solve the transient heat transfer equations, the Boundary Element Method is utilized, ensuring both accuracy and reduced computational cost. Unlike prior research, this work introduces an alternative shape parametrization approach that enables greater flexibility in the optimization process. The level-set equation is used to dynamically adjust the facade shape while maintaining the same material volume as a standard flat wall. A case study is conducted for Astana city and demonstrates the effectiveness of this approach and reveals optimized facade geometries that enhance energy performance despite the region’s harsh winter and summer conditions.