Overheating and Daylighting; Assessment Tool in Early Design of London’s High-Rise Residential Buildings

Bachir Nebia,Kheira Tabet Aoul

doi:10.3390/su9091544

Abstract

High-rise residential buildings in dense cities, such as London, are a common response to housing shortage. The apartments in these buildings may experience different levels of thermal and visual comfort, depending on their orientation and floor level. This paper aims to develop simplified tools to predict internal temperatures and daylighting levels, and propose a tool to quickly assess overheating risk and daylight performance in London’s high-rise residential buildings. Single- and double-sided apartments in a high-rise building were compared, and the impact of their floor level, glazing ratio, thermal mass, ventilation strategy and orientation was investigated. Using Integrated Environmental Solutions Virtual Environment (IES VE), temperature and daylight factor results of each design variable were used to develop early design tools to predict and assess overheating risks and daylighting levels. The results indicate that apartments that are more exposed to solar radiations, through either orientation or floor level, are more susceptible to overheat in the summer while exceeding the daylighting recommendations. Different design strategies at different levels and orientations are subsequently discussed.

Highlights

While the proportion of new flats is small compared to the total housing stock [37], the large number of overheating cases reported in this study suggests a considerable risk of thermal discomfort in newly-built flats at higher floors; this agrees with the study carried out by Vandertorren et al [38]
Since the current overheating assessment tools in the UK have either limited abilities to predict the overheating risk at an early design stage, or are too complex to use, this study aims to develop simple design tools that rely on a rapid assessment of overheating risk and daylight performance at an early design stage in high-rise residential buildings
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Summary

Introduction

In vulnerable urban environments such as London’s, where a 9 ◦C temperature difference was observed between the inner-city and the surrounding areas during the night-time of the 2003 heatwave [9], heat risk emerges as a significant climate change issue. The UK Committee on Climate Change (CCC) implemented a 20% reduction target on the space heating demand [10], resulting in an increased level of insulation in new buildings. This led to thermal improvements in winter [11,12] and a reduction in energy consumption for new and refurbished dwellings. It is difficult to compare the results from the different studies because of a lack of standardization in their input parameters [31]

Objectives

Methods

Results

Conclusion