Effects of latitude and building orientation in indoor-illuminance levels towards energy efficiency

Abstract

As a matter of concern in sustainable buildings, daylight is studied to improve the balance between visual comfort for the occupants and energy consumption. This study analyzed the effects of latitude and orientation on the sunlight illuminance level within a northwest/southeast-oriented hypothetical house, with a wide-glassed façade, by integrating the BIM and BEM methodologies. The house was located in five different locations showing different latitudes: Búzios, Brazil; Capri, Italy; Punta Cana, Dominican Republic; Dubai, United Arab Emirates; and Sydney, Australia. Five different studies were carried out for each one of them by using the Autodesk REVIT energy-analysis tool named Lighting; they included sun-path analysis, calculation of daylight factor and daylight autonomy, and evaluation of daylight illuminance levels. It was found that a high amount of sunlight enters the house on its rear side, where are located the most occupied rooms, predominantly in the summer season, in the afternoon hours; however, 67% of the total house is below the 2% of daylight factor threshold. Withal, the rear-side rooms are the ones that satisfy most of the time with illumination levels above 300 lux, with maximum levels varying according to the season. This research contributes to associating BIM and BEM methodologies as an option to improve the design of energy-efficient buildings, being possible to consider further improvements to enhance the illuminance in the rooms, both for the early design stages and for future retrofit plans.