Design-based natural ventilation evaluation in early stage for high performance buildings

Natural ventilation has been recognized as one of the most promising passive strategies to reduce building energy consumption as well as to improve indoor air quality and thermal comfort level. However, a lack of agreement on evaluation index for natural ventilation in early design stage is noticeable. The target of this paper was to develop a natural ventilation evaluation index for early-stage design. The study began by reviewing current practices of natural ventilation evaluation and identifying the problems of current indices. A Design-Based Natural Ventilation Potential was then proposed as the evaluation index of natural ventilation, especially for the early design stage. The proposed evaluation index covered both indoor air quality and thermal environment aspects for natural ventilation and take early stage design information into consideration, such as urban context and environment. The evaluation index was employed in a case study of an office building to illustrate the advantage of this index comparing to other evaluation indices. As a conclusion, the Design-Based Natural Ventilation Potential can provide more design-oriented result of natural ventilation evaluation in early design stage, which as a result will lead to a better urban built environment by enhancing the possibility of high performance naturally ventilated buildings.