An approach to urban tree daylight permeability simulation using models based on louvers

Abstract

In oasis cities urban forestation shades the lower level facades of buildings. It is thus crucial to analyze the distributional patterns of sun radiation produced by trees on facades. Nevertheless, the complexity of the canopies requires simplified representations for its study through simulation techniques. On the assumption that lighting behavior of trees, as sun control elements, more closely resembles a louver system rather than other frequently used solar control systems (e.g. perforated obstruction), the present study seeks to verify which of these formal simplifications adjusts better to the real case. The methodology used in this study relies on raytrace simulation of solar control system models generated with hemispherical images. Comparisons are made between measured data of vertical illuminance (lux) in situ and those obtained through simulation for each of the models. Louvers model showed a high degree of adjustment (RMSE 9%). This study may be useful to streamline the analysis of urban trees impact in daylight availability on building facades through simulation.