Cost study on remote source solar lighting system in high-rise residential buildings in Hong Kong

Hong Kong is a densely populated metropolitan city with limited land supply. The land cost is high. Majority of the residential buildings are developed into high-rise with a central core design of enclosed lift lobbies without natural lighting. Electricity is required to provide illumination continuously for 24 h. A remote source solar lighting system using side-emitting fiber optic as illuminators is designed to reduce the emission of greenhouse gases for providing illumination to these lift lobbies. Experiment was carried out to test the performance of the daylighting system and proved that the remote source solar lighting system could displace an average of 3 h of electric lighting in a day and reduce 6.7 × 106 kg of carbon dioxide emission in a year. A study on the cost of the remote source solar lighting system was conducted and compared to the cost of the conventional lighting systems. Both the maintenance cost and environmental benefit that could be offered by the remote source solar lighting system were also studied in detail. Although the side-emitting technology of fiber optic is still primitive, further development can improve the emission efficiency and allow the remote source solar lighting system to operate more effectively. The potential of applying the remote source solar lighting system to conserve environment is promising.