Unlike other solar technologies, core sunlighting involves capturing sunlight at the building envelope, concentrating it, transporting it and regulating its release deep within the building at useful indoor lighting levels, typically only 1 percent of outdoor illumination (Figure 1).
Core sunlighting systems have the potential to deliver illumination with the benefits of high-quality electric lighting while also providing the advantages of daylight, including excellent color rendering and substantial energy savings.
These benefits, however, will not become widely available until core sunlighting is both cost effective and seamlessly integrated within construction techniques.
Such daylighting methods already are practical and are completely compatible with core sunlighting systems, together forming a natural lighting system for the whole building.)
But just how inexpensive must a core sunlighting system be for the building industry to accept it?
It may be helpful to loosely classify core sunlighting systems based on the location of sunlight capture and degree of concentration, as depicted in Figure 3.
It could be argued that core sunlighting systems in the R2 and F2 categories correspond to the minimum total cost that was shown in Figure 3.
New approaches to energy-efficient lighting using core sunlighting mean that almost all areas of a building can be illuminated with sunlight whenever the sun shines, without requiring any increase in floor-to-floor height or large expanses of glazing.
and Moss-man, M., "Using core sunlighting to improve illumination quality and increase energy efficiency of commercial buildings", Association of Mechanical Engineers International Conference on Energy Sustainability, May 2010.