Daylighting using light pipes and its integration with solar heating and natural ventilation

Abstract

This paper reports on a study in the United Kingdom on the performance of light pipe systems that is a part of a multistage EC-funded investigation involving researchers in four European countries. Daylighting measurement carried out so far in the United Kingdom has shown that the light pipe transmittance was generally higher on overcast days than on clear days, although illuminance levels were higher on clear days. It was found that light pipes transmitted slightly less solar infrared than visible light. Laser-cut panels were tested and it has been shown that by fitting one to a light pipe much higher levels of daylight transmittance can be achieved for certain periods of the day. The work also investigated combining light pipe technology, natural stack ventilation and solar heating by integrating the light pipe with an air stack and passive heat pipes. Other partners within the research consortium have carried out work on daylighting simulation, daylight collectors and natural ventilation. In addition, a study of the statistical information on the main building types and their morphology in several European countries has helped to determine the most suitable regions for this technology. It seems that the building types with the most potential are educational, office and retail buildings. A prototype system has also been installed and monitored in a real building in Switzerland.