Hybrid lighting systems: Performance and design

Hybrid lighting systems simultaneously deliver daylight and electric light into the core of a building where they are combined and distributed via luminaires. The systems have only been developed in the last few years and accordingly there is little accumulated experience of light delivery or design methods. This paper presents measured data for a commercially available hybrid system located in the United Kingdom. The performance of the hybrid system is compared with that of a tubular daylight guidance system. The results are discussed in the context of use of the systems for a range of sky conditions. Design recommendations and limitations to address knowledge shortfalls for hybrid systems are put forward.