A Field-validated Multi-objective Optimization of the Shape and Size of Windows Based on Daylighting Metrics in Hot-summer Mediterranean and Dry Summer Continental Climates

Abstract

This study aims to determine the optimum size of windows based on the window-to-floor ratio (WFR) for the main cardinal directions in Hot-summer Mediterranean (Csa) and Dry Summer Continental (Dsa) climates (Köppen–Geiger classification system) by carrying out a multi-objective optimization that relies on three dynamic metrics of Useful Daylight Illuminance (UDI-a (autonomous)), Daylight Autonomy (DA), and Annual Sunlight Exposure (ASE1000,250) in Radiance version 5.1. A validation against field measurements is conducted under an overcast sky with an illuminance of 11000 lux. The Pareto front is used to pick the best solutions for evaluating the most optimized solutions. Accordingly, the minimum standards for cardinal directions in each climate are defined. The minimum suggested WFR for the Dsa and Csa climates for the south-, east-, north-, and west-facing windows are 20%, 15%, 20%, and 15% (Dsa) and 20%, 20%, 25%, and 20% (Csa), respectively. Furthermore, the results show the shape and relative proportions of windows (vertical/horizontal) have a significant effect on the metrics. As a result, this paper introduces the “Proportion Ratio” as a new indicator for designing windows. © 2020 The Author(s). Published by solarlits.com. This is an open access article under the CC BY license (https://creativecommons.org/licenses/by/4.0/).