Classification of indoor daylight enhancement systems

In a dense urban environment, sky obstruction caused by high rise buildings causes minimal daylighting for interiors on lower floors and in deep interior spaces. Innovative daylighting systems can be used to enhance daylighting indoors using available sunlight. This paper presents an overview of recent developments of innovative daylighting systems. The daylighting systems, which are classified as light guiding, light transport, light diffracting, hybrid and integrated systems, have been reviewed and a comparison has been made with respect to ease of integration, durability, maintenance, availability, efficiency, light output and transportation. Suitability of climate has been identified with respect to each daylighting system. Recent research and development involves hybrid and integrated systems which have the advantage of providing lighting irrespective of external sky conditions. The advantages and disadvantages of each system are summarized. Compared to active systems, passive systems are environmentally friendly and their efficiencies are also higher. It is inferred that each system has its own unique principle of light transmittance and is suitable for certain climates. More research is required on developing daylighting systems which are environment friendly, less energy intensive, cost-effective and having ease of integration.