Thermal comfort assessment of underfloor vs. overhead air distribution system

Abstract

This study presents numerical simulations of thermal comfort and contaminant removal in an air conditioned office room with two typical air distribution systems: under-floor and overhead. Well-known finite volume method was employed in 3D and 2nd order upwind scheme was used to discretize governing equations. SIMPLE algorithm was used for coupling velocity and pressure fields. Then, set of algebraic equations were solved in an iterative manner using ADI approach. After evaluating the utilized numerical approach by comparison of its results with the experimental data taken from relative literature, the study was expanded to reveal the effect of inlet position (Under-Floor Air Distribution (UFAD) system, angle of air inlet (Over Head Air Distribution (OHAD) system and comparison between two systems. Velocity, temperature, relative humidity, contaminant concentration, thermal sensation, Predicted Mean Vote (PMV) and contaminant removal factor was computed and used for assessing thermal comfort and contaminant removal characteristics of the office room in each under-investigation case. Results suggest that better thermal sensation and contaminant removal effectiveness may be obtained if typical air inlet diffuser setup used in both air distribution systems. Both simulated air distribution system, showed comparable thermal sensation. PMV was close to comfort zone in both configurations. The UFAD system had some advantages to OHAD system, especially in contaminant removal effectiveness. © 2012 Asian Network for Scientific Information.