OVERHEATING AND DAYLIGHTING IN LONDON'S TALL RESIDENTIAL BUILDINGS; AN OPTIMISATION QUEST

In dense cities such as London, the housing shortage is far from being solved and the number of highly glazed tall residential buildings is increasing at a high rate. With the desire to vertically densify London, apartments in high-rise residential buildings are at a different exposure to the external environment. Depending on their floor level and orientation, the apartments may experience different levels of thermal and visual comfort. The objective of this paper is to build, a simplified tool able to predict the internal temperatures and the daylighting level, and a design comparative tool that focuses on the rapid assessment of overheating risk and daylight performance in tall residential buildings. This paper addresses the issue by comparing different design variables of a single and double-sided flat in a high rise city based building, by changing the density of heat transfer, the thermal mass, the ventilation strategy and the orientation. Using Integrated Environmental Solutions Virtual Environment (IES VE), temperature and daylight factor measurements are used to create a parametric comparison tool to appraise the impact of each variable on the overheating risk and daylighting performances, and to generate a simplified tool to predict the internal temperatures and the average daylight factor. Results show that apartments, which are more exposed to the weather, because of their floor level or orientation, are more susceptible to overheat in the summer while exceeding the daylighting recommendations and vice versa. Therefore, there is a need to consider different design strategies at different level and orientations of a high-rise apartment building. Simple and practical design strategies, such as an appropriate ventilation system or an appropriate glazing ratio following the floor level of the apartments, could be adopted to mitigate the overheating risk and meet an appropriate daylighting level in the actual and future weather scenarios in London.