In the quest to create healthier and more energy-efficient office spaces, a groundbreaking study led by Alyaá Tabbah from the Department of Construction Engineering and Lighting Science at Jönköping University in Sweden is shedding new light on the complex interplay between light, human well-being, and energy consumption. Published in the *Journal of Daylighting* (translated to English as *Journal of Natural Light*), the research delves into the often-overlooked “beyond-visual” effects of light, offering insights that could revolutionize office lighting design and energy management.
Light, as it turns out, is far more than just a tool to illuminate our surroundings. It influences our physiology and psychology in ways that go beyond mere visibility. Tabbah’s study explores what is termed “integrative lighting,” which encompasses both visual and beyond-visual effects. These effects are influenced by a myriad of factors, including the quantity, spectrum, and directionality of light, as well as its timing, duration, and history.
To tackle this multifaceted problem, Tabbah and her team designed a comprehensive lighting simulation framework. Using advanced computational tools like Rhinoceros/Grasshopper, Lark, ClimateStudio, and Ladybug/Honeybee, they simulated various lighting scenarios in a single office setting. The simulations considered nine control points, four vertical viewing directions, and one horizontal direction, each testing eight different window sizes and various electric lighting combinations. The team also varied the melanopic content of the lighting—its ability to stimulate the ipRGC (intrinsically photosensitive retinal ganglion cells) cells in the human eye, which are crucial for regulating circadian rhythms.
The results of the study are both illuminating and thought-provoking. “Beyond-visual effects depend on light quantity, spectral composition, and spatial distribution,” Tabbah explains. “Increasing the window-to-wall ratio or the melanopic content of lighting alone does not ensure uniform beyond-visual performance.” This finding underscores the complexity of optimizing office lighting for both visual and non-visual benefits.
One of the key insights from the study is the importance of directing wall washers at opaque surfaces. This approach enhances background luminance, reduces glare, and improves retinal exposure, ultimately leading to better visual comfort and non-visual benefits. However, the study also highlights the challenges posed by temporal dependencies, which often require trade-offs between window size and lighting energy use.
For the energy sector, these findings could have significant implications. As buildings become increasingly energy-efficient, the role of lighting in overall energy consumption cannot be overlooked. By optimizing light levels, spectrum, and directionality at the right time, building designers and energy managers can create spaces that are not only visually comfortable but also energy-efficient.
Looking ahead, Tabbah advocates for the use of multi-objective optimization techniques to balance visual and non-visual outcomes. Automating adjustments to lighting systems based on these optimizations could further enhance well-being while maintaining energy efficiency. “Future approaches should use multi-objective optimization to balance visual and non-visual outcomes, automate adjustments, and enhance well-being while maintaining energy efficiency,” she says.
As the construction and energy sectors continue to evolve, the insights from Tabbah’s research could pave the way for smarter, more sustainable office designs. By integrating both visual and beyond-visual effects into lighting strategies, we can create spaces that are not only energy-efficient but also conducive to human health and productivity. This research is a significant step forward in our understanding of integrative lighting and its potential to transform the built environment.