FIELD STUDY OF ENHANCED DISPLACEMENT VENTILATION SYSTEM IN AN OFFICE

Abstract

This study proposes to evaluate the performance of an Enhanced Displacement Ventilation (EDV) system with two fans mounted on it in an office in the Zero Energy Building (ZEB) at BCA Academy. The objectives of this study are to determine the effect of the EDV system on the thermal characteristics generated in an actual office environment; occupant acceptability of the EDV system in terms of thermal comfort; and lastly if the introduction of EDV system improves the thermal comfort conditions in an actual office environment. Objective measurements and subjective assessments were conducted in 3rd level office of the ZEB@BCAA. Four subjects were specially chosen for this study as the survey done by the previous study show that they are dissatisfied with the conventional DV system in this office. The discharge angle of the flow from the fans was kept at 30o from the horizontal plane as it was found to be the preferred angle. Subjects have personal control over the fan speed, i.e., LOW, MEDIUM and HIGH mode, to suit their preference. It was found that the EDV system is able to achieve good stratification, which brings about good air quality at the occupied zone. The preferred fan speed for most of the subjects is fan speed (MEDIUM) at ambient temperature of 24.5°C ± 0.23. 100% of the subjects felt air movement with the introduction of EDV system. The overall thermal sensation of the subjects was enhanced as the two fans provide better thermal sensation to the subjects. It was also observed that without the fans, the upper body segments such as the torso, chest and shoulder have warmer thermal sensations as compared to conditions with the EDV system. Overall, 75% of the subjects felt that the EDV chair is effective in providing them with higher thermal comfort satisfaction. Some of the limitations are the EDV system was not been fully utilized throughout the study due to northeast monsoon season, which result in slightly lower temperature recorded in the office. Also, more EDV chairs can be provided to obtain a larger pool of sample size that can incorporate a wider range of age group and gender type.