Occupants' perception of air movements and air quality in a simulated classroom with an intermittent air supply system

The study reported herein builds on occupant response to an intermittent air jet strategy (IAJS), which creates periodic airflow and non-isothermal conditions in the occupied zone. Previous research has highlighted benefits of IAJS for the thermal climate and energy saving potential in view of human thermal perception of the indoor environment. The study herein explores the occupant acceptability of air movements and perceived indoor air quality. Thirty-six participants were exposed to three room air temperatures (nominal: 22.5℃, 25.5℃ and 28.5℃) with each having four air speed conditions (nominal: < 0.15 m/s under mixing ventilation (MV) and 0.4, 0.6 and 0.8 m/s under IAJS) measured at the breathing height (1.1 m). The results show that participants preferred low air movements at lower temperatures and high air movements at higher temperatures. A model to predict percentage satisfied with intermittent air movements was developed. The model predicts that 87% of occupants, in compliance with ASHRAE 55-2013 standard, will find intermittent air movements acceptable between 23.7℃ and 29.1℃ within an air speed range of 0.4 to 0.8 m/s. IAJS also improved participants' perception of air quality in conditions deemed poor under MV. The findings support the potential of IAJS as a primary ventilation system in high occupant spaces such as classrooms.