Effects of alley form on outdoor thermal comfort in traditional villages in Pearl River Delta

Abstract

Traditional villages in the Pearl River Delta effectively adapt to the hot, humid climate with proper forms of alleys and shading strategies. Studying these elements is valuable for village planning. Three different forms of alleys in Huangwu village were selected for summer microclimate measurements: common alleys, alleys with shading facilities and alleys bordered by buildings of varying heights. After validating simplified simulation models with ENVI-met software, two types (with or without shading facilities) of parameter-based models were created by altering aspect ratio ((Height (H)/Width (W)), orientation, width of shading facilities and height of surrounding buildings. The physiological equivalent temperature was used to assess thermal comfort levels and the findings have suggested that: (1) The quality of the thermal environment can be significantly different in alleys with different orientations. (2) Thermal comfort was significantly decreased when H/W was below 2. (3) Adding shading facilities could greatly improve thermal comfort, with optimal results when width is 1 m. (4) Analysis of combined effects of multiple form parameters on the thermal comfort of alleys, showed: (a) when two alleys exhibit identical H/W and orientations, thermal comfort is better where the surrounding buildings possess greater height; (b) thermal comfort was easier to adjust with lower surrounding buildings.