Daylight penetration into a deep interior space can be achieved by using a light tube strategy. This research investigates how effective a room's ceiling cavity can be as a daylight transporting system. The design, therefore, tries to answer the question "What is the optimal geometry for a ceiling cavity and inlet aperture to bring deeper daylight penetration and achieve a higher illumination level, measured at the back of a room, than that achieved by a typical high window opening?" Corporate affiliate 3M assisted this project by providing a prismatic and highly specular surface to cover the underlying geometry of the ceiling cavity. A 16' deep room section with a high window opening on one side was constructed as a test cell. Inside, sensors were set up to allow light measurement at task level along the depth of the room. Light rays were deflected by the geometry of the ceiling cavity, through a number of internal reflections on the highly reflective film surface, to a diffuser at the back. The three most promising geometric designs from scaled model tests were selected, installed and tested for efficiency in the full-scale test cell. / Master of Science

This thesis deals with the measurement of light tubes efficiency in laboratory conditions during lighting by almost direct light rays. It also deals with the measurement of the spectral reflectance of the reflective materials available on the Czech market. The comparison of the efficiency of different light routes and also the determination of the spectral qualities of different reflective materials are the aims of this thesis. The light tubes were measured by means of the cubic integrator. The light source was moved and manoeuvred by means of the automatic goniophotometer. The light source flow was determined by the method of the zonal flows. The data were calculated in the Matlab programme. The evaluation is both in the graphic and in the numeric forms. The result of the thesis is both the comparison of the reflective materials for light tubes qualities, and the evaluation of efficiency of the assigned light routes. The optimal variant can be then selected during designing of the light tubes route according to the results of the measurements.