The measured and predicted performance of passive solar light pipe systems

Passive hollow tubes consist of a light pipe transport section with, at the upper end, some device for capturing natural light and, at the lower end, a means of distribution Of light within the interior. The wider use of the systems is currently limited by the lack of quantitative design methods other than those based on empirical data. This paper presents results of laboratory and field measurement of luminous flux output and luminous intensity distribution for various configurations of passive solar light pipes. The results indicate quantitative performance and form the basis of a number of methods of performance prediction for a wide range of passive light pipe system configurations.