Energy performance assessment of climate adaptive building envelopes using shading masks

This study investigates the limitations of existing building energy simulation processes for Climate-adaptive Building Envelopes (CABE) and introduces a new method for evaluating them. Unlike static shading systems, CABE requires time-based geometric variation information as part of its operational schedule. To represent this variation, the most widely used CABE simulation processes involve multiple energy models, necessitating the assembly of hourly data from independent outcomes through a post-processing sorting process.

Another approach uses an energy model that integrates multiple geometries of the CABE system as shading elements. These are controlled through transparency schedules, which include time lag effects in energy load calculations, eliminating the need for additional post-data processing. Although both methods are widely accepted for assessing CABE’s energy performance, they are limited to a single set of geometric variations per simulation run. This limitation complicates the integration of parametric modeling and optimization techniques during the early design stages, potentially resulting in missed opportunities to develop optimal CABE design solutions.

To address these challenges, this study introduces a novel CABE simulation process called the Parametric Shading Mask Map (PSMM) system. The PSMM system captures the geometric variation of CABE by projecting its geometry onto a vertical surface positioned in front of a window, aligning with the sun’s movement. This vertical surface is then divided into a grid resembling static shading. Each shading element operates based on an on-off schedule, determined by whether the sun’s vector intersects with the CABE geometry. This grid-based shading system parametrically represents the geometric variations of the CABE system, regardless of its shape, similar to a shading mask.

Two test cases will be conducted to demonstrate the reliability and robustness of the PSMM system. The first test case will validate the PSMM method by comparing it with existing CABE energy performance simulation methods. The second test case will present the overall workflow of the PSMM system, showcasing how it easily integrates CABE’s geometric variations, in comparison to existing methods. A summary of CABE performance evaluation methods will be provided as a guideline to help architects and researchers select appropriate approaches for designing and analyzing CABE systems.

The PSMM system is expected to significantly contribute to the CABE design process by providing a new, design-oriented performance evaluation method not supported by existing methods.