Improving passive solar collector for fiber optic lighting

Increasing energy demand and cost are the main motivators for this research project, which utilizes solar radiation for lighting interior spaces in buildings. The objective is to use passive solar radiation collection coupled with fiber optic bundles to provide natural lighting. The research team proposes a novel passive fiber optic lighting system design, which collects the abundant supply of free solar radiation without using expensive tracking systems that require constant alignments year-round. The passive lighting system design will respond to several criteria. The exposed collector dome is fixed and capable of collecting as much light as possible on an average sunny day and robust to withstand all weather conditions. The fiber optic cable will deliver light up to 20 m or to the basement of a two story house; delivered light intensity must satisfy standard domestic lighting codes. The research focuses on two aspects of the system: the solar light collector and fiber optic distribution cables. In the initial project phase the dome of a commercially available tubular daylighting device is modified to enhance light collection. Preliminary tests indicate that it will be possible using gratings to redirect more sun rays into the tubular daylighting device, increasing the light captured. The next modification enables fiber optic bundles to be coupled to the system for light distribution to areas in a building. A parabolic mirror pair set-up as a compound concentrator inside the tubular daylighting device will concentrate light into the fiber bundle at the base.