Passive heat recovery wind tower: Assessing the overheating risk in summertime and ventilation heat loss reduction in wintertime

Wind towers are low-energy ventilation devices which can provide cooling and reduce buildings' energy use. However, during unfavourable climate conditions, wind tower operation could cause thermal discomfort and ventilation heat loss. There also has been very limited research into the overheating risk caused by wind tower ventilation. Therefore, this study explores the feasibility of the year-round operation of wind towers with solid tube heat recovery (THR) through computational fluid dynamics (CFD). The results show that within the mildcold months, the natural ventilation wind tower with THR raised the room temperature by an average of 3.1 degrees C, based on the set conditions. This extended the working period of the wind tower throughout the year, especially during mild-cold months. During summertime, the highest indoor temperature observed in the space ventilated by the wind tower with THR was 24.35 degrees C, which meets the static overheating criteria. The wind tower with THR reduced the ventilation heat loss by up to 8.1% in wintertime. It should be acknowledged that the wind tower with THR cannot provide satisfactory thermal comfort in cold months with outdoor temperatures below 9.41 degrees C, and more research should be conducted to improve the heat recovery efficiency.