Development of a simple light pipe from a Fresnel lens

Abstract

This research is to develop a simple light pipe from the Fresnel lens. Fresnel lens was applied to be a light source to supply natural light to a light pipe that made from a zinc sheet. The objective of the study is (1) find out the best focal length or focal distance of the Fresnel lens (size 28.5 cm × 28.5 cm), (2) the best range of a horizontal shaped tube, after that (3) the light pipe will be tested for an actual use with a 1 m² simulation room. The results found that the optimum focal distance of the Fresnel lens is in the range of 15 to 20 cm. with the luminance between 339 and 553 Lux. The best horizontal distance of the light pipe must be installed with mirrors to help reflect the light in the bend of the light pipe. The optimum length is 200 cm, with the luminance is 292 Lux. Also, the results from the actual test with the simulation room, when the installation of the LED lamps will increase the potential of the light pipe to be able to apply in the buildings or outside the buildings. The illumination that can be used to use the light pipe is approximately 400 Lux. Moreover, the research has conducted economic analysis. The study indicated that a light pipe will save electricity equal to 18.5 kWh/year, and the payback period of the light pipe is around 10.8 years.