Effect of urban form on microclimate and energy loads: Case study of generic residential district prototypes in Nanjing, China

Abstract

To conduct a more comprehensive evaluation regarding the correlations between urban form, microclimate and energy performance of buildings, this study investigates eight generic residential district prototypes in Nanjing, China. Cases are characterized based on form indices such as the floor area ratio (FAR), surface area ratio (SAR) and mean sky view factor (SVF). A co-simulation method combining ENVI-met and EnergyPlus is proposed to simulate the microclimate, represented by average conditions around the exterior surfaces of all buildings in the studied district, and building energy loads during typical summer and winter days. The results show that, generally, air temperature and direct shortwave radiation are negatively correlated with the SAR. The cooling and heating loads are negatively correlated with the FAR and SAR, and positively correlated with the mean SVF. The differences in energy loads can reach 23.4 % with obvious deviation of the regression analyses of hourly heating loads and air temperature if neglecting the microclimate effect.