Interior retrofit for efficient tropical daylighting in home office workspaces

Abstract

Home office workspaces have substantially increased all over the world and Malaysia is not an exception. However, existing residential buildings (ERBs) in Malaysia have been designed mostly for the purpose of accommodation, but not for office working, as far as daylighting is concerned. This situation is even more critical here as it is a tropical country with intense solar radiation and excessive sky luminance. This causes discomfort glare in many typical ERBs, which are mostly without external shadings. Due to limited flexibility for modification of the existing residential units by residents, interior retrofit can play a significant role in improving the visual environment. Not much research has been done focusing on interior retrofit in ERBs regarding visual comfort. This thesis aims to optimize tropical daylighting efficiency through interior retrofit in home office rooms (HOR) located in the ERBs in Malaysia. A questionnaire survey was conducted to find out the current scenario of HORs in terms of interior design profile in 11 ERBs in Johor Bahru. Based on the findings, a base model was derived to simulate daylight using the Radiance program in the Integrated Environmental Solution-Virtual Environment (IES-VE) software. Prior to the simulation experiments, a field measurement in a typical room was conducted to validate the software under the tropical sky. Then different design parameters including furniture layout, window glazing film, surface reflectance, internal light shelf and venetian blind were experimented through daylight simulation. Estimated work plane illuminance (EWPI) and standard daylight zone (SDZ) were evaluated for quantitative performance, while work plane illuminance uniformity ratio (IUR), Guth visual comfort probability (GVCP) and CIE glare index (CGI) were considered for qualitative performance. Findings showed that partial blind at upper window was the optimum design model for efficient daylighting in a room with indirect or reflected sunlight for all cardinal orientations. However, integration of a light shelf with partial blind at lower window was the best in a room with direct sunlight. In conclusion, this study provides evidence that a dynamic integrated model of light shelf and partial blind can be an effective alternative to the conventional interior shading devices. The finding of the study has shown how to improve the visual environments in home office workspaces in ERBs by changing the pattern of internal shading device in tropical areas.