Effects of anthropogenic heat on the urban wind-thermal environment in typical residential neighborhoods in Nanjing, China

● Neighborhood morphology affects anthropogenic heat dispersion. ● Seasonal analysis compares summer and winter anthropogenic heat impacts. ● Air-conditioning outflow enhances pedestrian wind speed by 87.6% in summer. ● High-rise, slab-type building showed less anthropogenic heat impact. ● Ambient air temperature changes relate to building density. Anthropogenic heat, such as heat generated by air-conditioning systems, has an essential impact on the urban wind-thermal environment in hot-summer and cold-winter regions. This study investigated the effects of anthropogenic heat on ambient air temperature and pedestrian-level ventilation rate across different seasons using CFD simulations based on six typical residential neighborhoods in Nanjing, China. The results indicated that the effects of anthropogenic heat on the wind-thermal environment of residential neighborhoods was more significant in summer. In summer, air-conditioning operation increased the pedestrian-level ventilation rate by up to 87.6%, whereas in winter, it slightly reduced the pedestrian-level ventilation rate by up to 46.5%. Anthropogenic heat created air temperature differences between the pedestrian level within residential neighborhoods and the atmospheric level. High-rise, slab-type building neighborhoods experienced less impact from anthropogenic heat. In summer, the probability of an air temperature difference below 0.5 K was 35.0%, while in winter, it was 27.5%. In addition, ambient air temperature differences were found to correlate with building density but not related to floor area ratio, surface area ratio, and sky view factor. These findings can provide a valuable reference for residential building design to mitigate the negative impacts of anthropogenic heat in Nanjing.