A novel method for making laser cut panel based daylight collector coupled to a tubular light guide

Abstract

The work in this paper focuses on the development of a daylighting device which can increase the light output for longer lengths of hollow mirrored light pipe. The device proposed is passive, easy to build, and inexpensive. It uses the concept of total internal reflection in acrylic laser cut panels (LCPs) and extends the idea into a complete collector based on mathematical modelling. The novel method of fabricating laser cut panels with steep cutting angles and partial depth cuts has been discussed in this paper. This method has been combined with weight optimisation to make a lightweight yet efficient collector with no laser cuts exposed to the atmosphere. The simulation results of this collector have been compared with a flat acrylic plate coupled to a light pipe and experimental validation of simulation has been performed using a prototype. The simulation results for collector coupled to 80% reflective light pipe have shown up to 4.3 times the illuminance on model room floor as compared to light pipe with a flat plate on 21 December- the low solar altitude season for which the collector was primarily designed. Another simulation of a real dimension office space with multiple collectors shows that at least 175 lx of average illuminance is available on the work surface with 227 cm2 cross-section light pipes.