Effectiveness of intermittent personalized ventilation assisting a chilled ceiling for enhanced thermal comfort and acceptable indoor air quality

Abstract

In this work, the performance of an intermittent personalized ventilation system coupled with a chilled ceiling was evaluated based on its ability to provide comfort and protect occupants from passive contaminants. A 3-D computational fluid dynamics model was used to predict the airflow fields in the space (velocity, temperature, and concentration). The model's predictions were experimentally validated in a climatic chamber equipped with a chilled ceiling and a personalized ventilation. Good agreement was found between experimental results and the computational fluid dynamics model.A case study was then conducted for different chilled ceiling and personalized ventilation configurations at an average personalized ventilation flow rate of 7.5 L/s, It was found that at lower chilled ceiling temperatures (16 °C), it is recommended to operate the personalized ventilation under steady flow since the intermittent personalized ventilation doesn't bring any enhancement in comfort and air quality. However, for conventional chilled ceiling temperatures at 20 °C, an intermittent personalized ventilation operated at 0.5 Hz improved comfort compared to steady personalized ventilation. Moreover, the intermittent personalized ventilation was able to achieve 7.52% and 15.04% energy savings compared to a steady system and standalone chilled ceiling respectively, under similar comfort conditions.