Using Core Sunlighting to Improve Illumination Quality and Increase Energy Efficiency of Commercial Buildings

The lighting industry has been challenged to deliver high quality illumination while using less electrical energy and, to achieve this, it is generally agreed that it is a good idea to incorporate daylighting strategies. We have developed a new system that is capable of delivering sunlight deep into the core of multi-floor buildings. This system has the potential to reduce the energy required for illumination in standard commercial buildings by at least 25%, reduce peak electrical power demand when it is needed, and provide high quality illumination with excellent color rendering characteristics. This result is achieved by delivering sunlight to the interior regions of the building, thereby replacing electric lighting on average 75% of the time each day that the sun shines within six core daylight hours. As a result of both its cost-effectiveness and the ease with which it can be integrated into standard building construction, this is the first core sunlighting system with potential for widespread adoption. An initial demonstration shows a substantial reduction in the electrical lighting load and enables an evaluation of the spectral quality of the sunlight illumination from the perspective of the occupants.