Enhancing outdoor shading without diminishing indoor daylight integration: simulations from Colombo, Sri Lanka

The new development proposals for Colombo, Sri Lanka, advocate high density developments with high Floor Area Ratios. Literature suggests the relationship between the “In” and “Out” plays an important role in energy efficiency targets in an urban setting. The study attempts to identify the probable impact of shade created by urban canyons towards energy efficiency, via daylight integration and reduction of cooling loads. Using 'Autodesk Ecotect Analysis' the study assesses the impacts of the common types of urban canyon geometries and a representative building typology, in Colombo. Parameters representing the urban canyon, the form and the building envelope were modelled for Shade, Daylight Factor (DF), Cooling Load and Predicted Mean Vote. Statistical analysis of the results indicate that only 34% of the outdoor shade was attributable to the selected parameters while 89% of canyon parameters influenced Daylight Factor. However shade on facade did not have a significant correlation with the Daylight Factor. This could be used as an advantage to minimize cooling load (with maximal shading) without compromising daylight availability. Energy efficient buildings in the tropics could thus aim for an integrated approach in managing indoor and outdoor climates.