Decision-making pathways to daylight efficiency for office buildings with balconies in the tropics

Daylight in the indoor environment is directly influenced by the building surroundings, envelope and its shading devices, such as balconies. Despite their potential in contributing to increase shaded periods and, at the same time, act as a daylight distribution system, balconies are not designed to their full potential when used in office buildings and the literature lack studies that investigate the effect of balconies on their luminous performance. This study aims to explore this niche: the integration of balconies to the design of office buildings in the tropics, in order to improve their daylight performance. The research method was based on a parametric design approach in combination with daylight simulations, while combining a systematic analysis with a data mining algorithm. The study revealed successful combinations of building design parameters as well as important cut-off points for design decision-making to achieve daylight efficiency in typical mixed-mode office buildings in the city of São Paulo, Brazil. Results provided multiple design routes to achieve successful performance targets showing that, if properly dimensioned, balconies could be an efficient shading device and daylight diffuser. As a key contribution, successful combinations of design parameters that allow deeper balconies to yield better Useful Daylight Illuminance levels were identified. Further details about when balconies stop influencing daylight performance results as well as when an increase in balcony depth becomes beneficial to performance were reported in attempt to develop design guidelines for the early design stages for office buildings in São Paulo.