DAYLIGHTING in ENERGY EFFICIENCY A case of office building in Kathmandu

Abstract

Architecturally, light and design is a collective term where light illuminates the form, space, texture, color and vibe of the space. It is the only medium to perceive object, which can be in the form of both daylighting and artificial lighting. Office buildings are operated for 7 – 8 hours daily on weekdays where light is most to carry out any type of work. Several researchers have found daylighting is beneficial to human psychologically and in reducing the active energy consumed by the building for illumination. The office buildings of Kathmandu are turned spaces and rarely designed while the designed ones are with deep floor plates or with glass curtain wall which results in visually uncomfortable indoor environment. The research aimed to investigate the passive strategies for illuminating space maintaining visual comfort and at the same time reducing the use of active energy. Using the climate data from DHM, an office building floor was simulated in Velux Daylight Visualizer 3, with varying window wall ratio (WWR) ranging from 10% – 100% and Autodesk Ecotect software, 2011 to analyze daylighting level and energy consumption respectively w.r.t. to WWR to deduce the best WWR required to meet the required optimum illumination in the office building while reducing energy consumption which is a quantitative analysis. The result showed that 30% window wall ratio is optimum for the office building of Kathmandu which holds clerical work as a prime task. The lighting energy is reduced by 66.92%, cooling energy is reduced by 10% and the total energy consumption of the floor is reduced by 5 % with changed WWR and window configuration. The research concludes that the daylighting findings will be helpful to designers in the early design phase, academic researchers and also to prepare guidelines, policy maker to create visually and functionally friendly space.