ABSTRACT
Conventional static collectors in light pipes are not efficient due to the seasonal and diurnal movement of sun. Further, the varying latitude of the different locations on earth necessitates a collector which considers the related solar position. A single solution or design of a solar collector may not be ideal. Solar position of a location is characterized by the solar altitude and azimuth angle. Profiled Fresnel collectors have a profile such that any surface is normal or nearly normal to the solar rays incident on it whereas the other surfaces receives solar radiation with varying intensity. The collector profile will vary depending on the latitude of the location used. The present study focuses on the design of passive daylight fresnel collectors for enhancement of daylighting in light pipes using a daylighting tool which suits the solar position in the geographical location under study. The profile angle can be determined and the collector design can be developed.
Locations with varying solar azimuth angle and altitude angle were selected and the collector profile was determined. The average of solar altitude angles of corresponding period was calculated and deducted from 90°. This represented the angles for the profile of the collector. Each face of the collector was profiled so that it was nearly normal to the sun for certain period of a day corresponding to the solar azimuth angle. Profiling the collectors was done with respect to the unique geographical location so that uniform day lighting throughout a day irrespective of the solar altitude and azimuth can be obtained. Collection of daylight can be maximized by customizing the collector according to the location.
