Energy Efficient Facade Lighting

Façade lighting of buildings serves many functions, one being to communicate to the public domain. This project investigates the design of an energy-efficient lighting solution to highlight architectural details of façades based on optical fibres. A pilot study of the application was made in order to test the photometric characteristics and to further explore possible applications for façade lighting. The measurement results show that an optical fibre of 80 m can be fed bi-directionally with a laser at either end and provide a relatively uniform light output. Within the projects three coloured laser types (red, green and blue) were tested. One of the main challenges was to control the temperature of the elements that required outdoor casing for extreme weather conditions (temperatures below -10°C and above 30°C). Compared to a conventional optical fibre setup, which uses a metal halide reflector lamp, the overall system is more energy-efficient. The conventional system with a MH-R base projector uses 190 W and serves 20 m. One laser system uses 71 W and lights up 40 m. The highly collimated laser beam reduces the coupling losses, when the light enters the optical fibre, thus increasing the energy efficiency substantially. 

The main conclusion is that the project concept is feasible and offers an energy-efficient alternative to conventional systems. Recommendations for future work will mainly focus on product design and technical improvement to reduce the case sizing.

Prof. Dr.-ing. habil. Alexander Rosemann
Dr. Myriam Aries
Wies Westerhout 
Mitchel Hoos

Delft University of Technology:
Dr. Truus Hordijk

Industrial partner:
BL Innovative Lighting, Canada
Betty Lou Pacey

The project was funded by the 2014 3TU.Bouw Lighthouse program ( and was carried out as a collaboration between the TU/e Building Lighting group and the TU Delft Building Physics group.

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