In the scorching climates where the sun reigns supreme, designing classrooms that bask in natural light without succumbing to glare and overheating has long been a puzzle for architects and engineers. A recent study published in the *Journal of Daylighting* (translated from French as *Journal of Daylight*) offers a promising solution, demonstrating how tubular daylight devices (TDDs) can be optimized to strike the perfect balance between daylight and comfort. The research, led by Fatima Zohra Ferahta from the University of Batna in Algeria, could reshape how we approach daylighting in high-solar climates, with significant implications for energy efficiency and occupant well-being.
Ferahta and her team focused on a 35 m² classroom in Batna, a city known for its intense sunlight, to evaluate nine different TDD configurations. These devices, which channel sunlight into interior spaces through reflective tubes, came in three diameters—250 mm, 350 mm, and 540 mm—and were tested in configurations of one, two, or four units. The goal was to find the optimal setup that maximizes daylight while minimizing glare and overheating.
The study employed a multi-criteria optimization approach, weighing factors such as Daylight Autonomy (DA), Useful Daylight Illuminance (UDI), Annual Sunlight Exposure (ASE), and uniformity. The results were striking. The 4×350 mm configuration emerged as the top performer, limiting overlit areas to just 20.7%—a significant improvement over the 4×540 mm setup, which overlit 37.1% of the space. Moreover, the 4×350 mm configuration drastically reduced glare hotspots, offering a more comfortable environment for students and teachers alike.
“Prioritizing daylight quality metrics like UDI, ASE, and glare control over simply maximizing illuminance is crucial in sunny climates,” Ferahta emphasized. This insight aligns with international standards such as EN 17037 and LEED v4, which emphasize the importance of balancing daylight with visual comfort.
The findings have profound implications for the energy sector. By optimizing TDD configurations, schools and commercial buildings in high-solar climates can reduce their reliance on artificial lighting, cutting energy costs and carbon emissions. The research also highlights the importance of tailored solutions—what works in one climate may not work in another, and a one-size-fits-all approach simply won’t cut it.
As the world increasingly turns to sustainable design, Ferahta’s work offers a roadmap for improving visual comfort in educational spaces and beyond. The study not only provides actionable insights for architects and engineers but also underscores the need for continued innovation in daylighting technology. With further research and development, tubular daylight devices could become a cornerstone of energy-efficient, comfortable, and sustainable buildings worldwide.