Comparison of Indoor Air Distribution in a Ceiling Cooling Room with Different Mechanical Ventilation Systems

Abstract

This paper presents an experimental study concerning the influence of ventilation system type on indoor air distribution in a ceiling cooling (CC) room with mixing ventilation (MV), underfloor air distribution (UFAD) and stratum ventilation (SV) when the internal or external cooling load was increased from 41.5 W/m2 to 69.5 W/m2. The distributions of indoor air temperature, air velocity and contaminant concentration were measured and evaluated by the vertical air temperature difference, turbulence intensity and contaminant removal effectiveness, respectively. The results show that when the ceiling surface temperature increased from 17.0°C to 26.0°C, the vertical air temperature differences, turbulence intensities and contaminant removal effectiveness were 0.2°C-0.4°C, 27%-34% and 0.53-0.85 with CC+MV, 0.2°C-1.2°C, 27%-43% and 0.68-1.25 with CC+UFAD and 0.3°C-0.9°C, 24%-40% and 0.5-0.83 with CC+SV. The CC+MV had the most uniform distributions of indoor air temperature and velocity, whereas the CC+UFAD had the most non-uniform distribution of indoor contaminant concentration.