Human perception of room temperature and intermittent air jet cooling in a classroom

Abstract

Steady indoor environments are perceived poor at high temperatures and require a high energy input to cool to comfortable operative temperatures. The introduction of airflow variations in such environments improves occupant perception and is shown to be far more energy efficient than cooling the entire space as only the occupants’ are cooled. However, with this method the risk of draft is high and use of velocity variations reduces the risk. This paper discusses and compares two occupant cooling methods in a classroom setup. Cooling by reducing the room temperature and enhanced convective cooling with intermittent air velocities. The experiments were performed in a full scale mockup classroom with a total of 85 student-participants. In study 1, participants sat in a classroom for about 60 min, in one of two temperature conditions: 20℃ and 25℃. In study 2, all participants sat in a room with a temperature of 25℃, but airflow variation in the sitting zone was manipulated. In both studies, the participants performed various tasks and answered questionnaires on their perception of the indoor climate. As shown here, higher classroom temperature deteriorates human perception of the indoor climate, and the use of intermittent air velocities improves the perception of indoor climate just like cooling by reducing the room air temperature. The results reveal that convective cooling can effectively be used as an energy efficient method of cooling in school environments.