Effect of Different Ventilation Systems on Concentrations of Indoor Particle Emitted from Floor of the Office

Abstract

A three-dimensional numerical simulation of airflow, temperature, and pollutant concentration distributions with underfloor air distribution (UFAD) system and displacement ventilation (DV) systems are presented for different operating conditions. Since the particles deposited on the floors can be re-introduced into the air through re- suspension and then constitute a threat to human’s health, an optimal ventilation system is required to reduce the indoor air particle concentrations. In the present study, the effects of different systems on the concentrations of indoor particles are numerically investigated by an Eulerian-Lagrangian method, and the RNG k-ε model is adopted for the simulation. Three different supply air velocities (0.2-0.4 m/s) and different supply air temperatures (20 ℃, 22 ℃ and 24 ℃) are considered in the simulation. Meanwhile, the thermal effect of the human body on the micro-environment and its interaction with the surrounding environment are comprehensively evaluated. The simulation results shows that for the UFAD and DV systems, good performance of particle removal is obtained with the high air supply speed for the DV system, while under larger temperature gradient of the indoor environment, the UFAD system is capable of reducing the concentration of the particles emitted from the floors with lower air supply speed.

Keywords

• underfloor air distribution
• displacement ventilation
• thermal plume
• particle concentration
• human micro-environment