Development of a simple light pipe from a Fresnel lens

Abstract

This research developed a simple light pipe from using a Fresnel lens as a light source to supply natural light to a light pipe made of a zinc sheet. The objectives of the study were to (1) find the best focal length or focal distance of the Fresnel lens (size 28.5 cm × 28.5 cm), (2) the best range of the horizontal shaped tube, and (3) the light pipe was tested actual use with a 1 m2 simulation room. The results showed that the optimum focal distance of the Fresnel lens was in the range of 15 to 20 cm with the luminance between 339 and 553 Lux. The best horizontal distance of the light pipe requires that mirrors be installed in the bend of the light pipe so as to reflect light. The optimum length was 200 cm with the luminance is 292 Lux. The results from the actual test with the simulation room indicated that the installation of the LED lamps increased the potential of the light pipe to be able to apply in the buildings or outside the buildings. Appropriate illumination for the light pipe was approximately 400 Lux. The study indicated that a light pipe could save electricity of 18.5 kWh/year, and the payback period of the light pipe is around 10.8 years.

Keywords

• light pipe
• fresnel lens.