Influence of ceiling fan induced non-uniform thermal environment on thermal comfort and spatial adaptation in living room seat layout

Abstract

Ceiling fans are common in Indian residences as airflow is important for thermal comfort. Ceiling fans are generally located in the centre of room for good distribution of airflow though airflow is limited to a small area and air velocity is reduced with increasing distance from the fan. Occupants spatially adapt while deciding seating layout considering various functional factors including thermal comfort. This study evaluates the effect of ceiling fan induced non uniform airflow on thermal comfort conditions in four living room seating layouts. The thermal environment was monitored in a living room and ceiling fan induced airflow was measured to study the distribution of airflow in four selected furniture layouts. The thermal environment in seats varied widely due to non-uniform distribution of airflow in the space. Thermal sensations in 12 seating positions of 4 different layouts were analyzed using Tropical Summer Index (TSI) and Predicted Mean Vote (PMV). Thermal comfort conditions in different seats improved at higher fan speeds in all layouts. TSI and PMV based thermal sensations varied from ‘Too hot’ to ‘Slightly Cool’ between warm summer and cool winter tropical seasons. The number of seats with ‘Too Hot’ thermal sensation were reduced at higher fan speed. Overall, seats farther from the fan experience relatively hotter thermal sensation in summer months and are not affected by fan speeds. The study emphasizes the relevance of moveable furniture and role of spatial adaptive behavior in room layout design, where required airflow for thermal comfort is not available within the space.