Fifty years of building core sunlighting systems - Eight lessons learned

Building core sunlighting systems (BCSS) are developed to deliver daylight where it can not be delivered by the conventional methods. A brief history is given of researches and developments into the BCSS over the last fifty years, in addition to a short description of the technologies and components of eighteen fully developed or commercialized systems. The paper classifies and compares the BCSS according to their design approaches so as to conclude the common features of the successful systems. Eight lessons learned have been addressed. The BCSS are technically powerful enough to provide lighting for remote and windowless spaces within buildings, but a couple of significant shortcomings hinders their popularization: cost prohibitive and application limitations. In addition, components costs/performance efficiency trade-off is one of the most fundamental decisions the BCSS designer must make. Finally, the paper presents the most recent design approaches that have been developed to overcome the identified failings.