Effect of local climate zone morphology on ventilation availability and thermal performance

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ABSTRACT In urban areas, the constantly altering morphological environment gives rise to a local thermal environment significantly different from the climate of surrounding areas. This study uses the Local Climate Zone (LCZ) classification system to analyse these variations in the local thermal environment, focusing on ventilation availability and its impact on building thermal performance. LCZs, representing high- and medium-density building clusters, were analysed in a boundary layer wind tunnel set-up and a parametric analysis using RSM was done to explore the impact of urban morphology variables on ventilation availability in the Cradle Sc-stream tool. The ventilation data obtained from the CFD analysis were further used to morph the standard weather file of the representative location. Later thermal performance assessments using the morphed weather data and the standard weather data were carried out for a representative residential building in the TRNSYS tool. The results show that there is considerable variation in ventilation availability and thermal performance of built environment across LCZs and, apart from the LCZ morphology, variables such as Block staggering and wind incidence angle also cause this variation. The study shows that building thermal performance assessments might result in significant errors if the local thermal environment is ignored.