The current research studies the impact of vertical green walls (VGWs) attached to building facades on indoor daylighting performance in hot-arid climates. The study used a combined approach of field experimentation and simulation. Two identical experimental rooms were constructed on the campus of Jordan University of Science and Technology (JUST), one with a green wall system and one as a base case. Illuminance levels in both rooms were measured under real sky conditions using lux meters. On the other hand, simulation models were developed in DesignBuilder and Velux software and validated using the experimental data. The VGWs, consisting of Hedera helix with varying foliage densities and cavity depths, were evaluated across different window orientations (east, west, and south) and during three seasonal periods (March, June, and December). The results demonstrate that VGWs can significantly reduce excessive illuminance and improve daylight distribution, with performance strongly influenced by orientation, foliage density, and cavity depth. For direct green walls, a 40% foliage density provided the most balanced daylight performance for east and west orientations, while 60% foliage density emerged as the optimal scenario for the south façade due to its ability to control excessive brightness and improve distribution. For the indirect green wall, shallow cavities (25–50 cm) had minimal influence on the east and west façades, while deeper cavities (75–100 cm) enhanced daylight penetration. On the south façade, shallow cavities (25–50 cm) performed best, whereas deeper cavities increased glare potential. Overall, the study demonstrates that VGWs are an effective passive design strategy for improving daylight quality, reducing visual discomfort, and supporting energy-efficient building design in hot-arid regions.
Alkhatatbeh et al. (Sun,) studied this question.