Combined Daylight Systems for Lightpipe Applications

The European research project ARTHELIO has examined the possibility of guiding daylight into deeper building interiors using hollow light guides. Within this project, a goniophotometer was developed and built up to measure the luminous intensity distribution of lightpipes. In two demonstration sites, the daylight utilisation by the hollow light guides combined with heliostats has successfully been demonstrated. Daylight is collected by heliostats and enters the building. It is guided along hollow light guides and coupled out along its way to illuminate the building interior. Measurements show that the prototypes help to decrease the energy consumption for electric lighting of the building. The advantages of lightpipes in a daylight system can also be shown in a hybrid system. The maintenance costs of lightpipe applications are inexpensive so that the variable costs of their operation are reduced. Current research activities at Technical University of Berlin deal with this topic.