For centuries, natural light was the only efficient source of light available. Fundamental objective of architecture was to create spaces with big openings so the natural lighting to enter in the interior of buildings.
The contiguous use and production of electric energy have created serious environmental problems. The energy crisis in the beginning 1970 forced the researchers of buildings to re-examine the possibilities that offers the natural lighting.
The objectives that are placed through the creation of systems of natural lighting for the rooms of a building are: to lit up sufficiently all the spaces of a room according to their use, create an optical environment with the better possible quality of lighting and simultaneously the consumption of electric energy to be as much as possible lower. There are several daylight systems that help in achieving this goal. Light shelves, sun pipes, heliostats and the anidolic ceiling systems with which we dealt more extensively are some of the systems. More specifically, the anidolic ceiling systems, use the optical properties of compound parabolic concentrators to collect diffuse daylight from the sky and through a specular light duct transports the light part to the back of room. The primary objective is to provide adequate daylight to rooms under predominantly overcast sky conditions. This essay analyzes the way which the anidolic ceiling systems function and through measurements in models is calculated his performance.