Introducing natural lighting into the enclosed lift lobbies of highrise buildings by remote source lighting system

In metropolitan cities like Hong Kong where land value is high, highrise commercial and residential buildings with “central core” design are developed. The lift lobbies in the buildings are usually located in the centre of the building to free up peripheral areas to provide valuable exterior view. The lift lobbies have no window provisions and electric lighting is switched on for 24 h continuously consuming non-renewable energy. Different types of light guides/light pipes have been proven to be capable to transfer daylight into deep floor plan during both clear sky and overcast periods. However, the thickness of light guide requires 3 m headroom clearance for installation whilst the headroom of the highrise buildings is usually limited to 2.8 m in order to build more storeys. In this research, a remote source lighting system (RSL) is introduced to illuminate the enclosed lift lobbies. The system composed of prismatic light pipe and optic fiber to address the problem of limited headroom. Simulation of the system was carried out and reported in the paper, indicating that this lighting system can solve the energy consumption problem in the lift lobby in terms of renewable energy use and natural lighting application. This research concentrates on highrise residential buildings.