Dynamic metrics of natural ventilation cooling effectiveness for interactive modeling

• Published in: Building and environment 2020-08, Vol.180, p.106994, Article 106994
• Main Authors: Yoon, Nari, Norford, Leslie, Malkawi, Ali, Samuelson, Holly, Piette, Mary Ann
• Format: Article
• Language: English
• Subjects: Air flow; Building design; Building simulation; Cooling; Cooling effects; Design; Design parameters; Energy conservation; ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; Interactive modeling; Key performance indicators; Natural ventilation; Performance evaluation; Thermal mass; Ventilation; Ventilative cooling
• ISSN: 0360-1323; 1873-684X
• DOI: 10.1016/j.buildenv.2020.106994

The evaluation of natural ventilation potential for cooling indoor spaces during the early design phases is of great interest to researchers and practitioners. Among various definitions and usages for natural ventilation potential (NVP) in early design evaluation, this paper reviews and identifies the key performance indicators, and proposes two new dynamic metrics—natural ventilation cooling effectiveness (NVCE) and climate potential utilization ratio (CPUR). The metrics are dynamically responsive to various design options, in both steady and transient states, allowing consideration of thermal mass. Assisting in design development processes, the metrics quantify how well indoor spaces make use of natural ventilation's cooling capacity. Case studies are presented to demonstrate how NVCE and CPUR enable designers to evaluate the predicted performance and how to apply the information to improve building design. The results of the design iterations showed that the relationship among various design parameters should be dynamically understood in order to evaluate the performance of natural ventilation, confirming that “the more the airflow, the greater the potential,” and “the heavier the thermal mass, the greater the energy saving” were not always true. •Existing natural ventilation performance metrics are reviewed.•New metrics quantify the cooling effectiveness of natural ventilation in buildings.•The metrics can consider both steady and transient conditions.•The cooling effectiveness can vary significantly even under the same climate.•The metrics facilitate interactive design process, assisting decision making.