Creating sunlight rooms in non-daylit spaces

Mike Wilson, Axel Jacobs, and John Solomon, LEARN, University of North London, UK
Wilfried Pohl and Andreas Zimmermann, Bartenbach LichtLabor GmbH, Austria
Aris Tsangrassoulis, National and Kapodestrian University of Athens, Greece
Marc Fontoynont, Dept. Genie Civil et Batiment, ENTPE, France

Keywords

fibre optics, liquid optics, remote light sources, sunlight, fresnel lens, heliostat

Abstract

A wide variety of heliostats have been developed over the last 20 years. These allow the focussing of sunlight into a light transmission system for distribution of the light to a part of a building with no access to daylight. This light transmission system may be fibre optics or more recently liquid optics. The distribution of light from a single light source through fibre optics has been available for many years although the system efficiency has been very low and the output restrict to a point source of light. Commonly tungsten halogen sources (inherently of low efficacy) or metal halide lamps have been used. The UFO (Universal Fibre Optics) project part funded by the European Commission Energie programme under contract ERK6-CT-1999-00011, coordinated by the University of North London, has developed a system for the integration of sunlight through a heliostat and liquid optic with an artificial source of light and a fibre optic system. The light from the liquid fibre and from the fibre optic are integrated using a transparent acrylic material with a speckled surface. A prototype system is being demonstrated at the University of Athens during the summer of 2002.