A model of particulate matter dispersion from unfiltered air conditioner indoor

The air conditioner is used not only for indoor temperature control but also as a particulate filtering system. However, bad maintenance of the air conditioner would lead to the damage of the filtering system. The result is a bad indoor air quality due to particulate matters depositing from outdoor. By the fact that a room with an air conditioner system is isolated, the risk of the human to be exposed is high. In this research, we built a model to simulate the particulate dispersion from air conditioner without active filtering system to find the effective range of the exposure. The research is purposely to model particulate matters, especially for PM2.5 and PM0.1. The model was built in the Navier-Stokes equation for incompressible fluids by using a Lagrangian approach in the grid system. The model simulated the dispersion of particulate matters in an 8 × 8 × 3 m room with a single air conditioner. The temperature of the room was settled at 24°C without any external particulate source. The speed of the airflow was set at 3 m/s while the concentration of the PM was set by change the air conditioner temperature setting. In the simulation, we found the increase of the effective range of particulate matters in the function of time. In the initial condition, the particulate matters are dispersed into the ceiling with the highest concentration. In the less than 5 minutes, our simulation shows the particulates dispersing in the whole room in the varied concentration. In the minute 50th, the concentration is similar to the air conditioner exposure. Our measurement in real condition showed a similar condition by a maximum different of 15% than the simulation both in the dispersion time and 2.5% in the concentration. These results were achieved after we compared the simulation in t time concentration with the real particulate dispersion in the identical room dimension with the simulation. In conclusion, the model can be performed to simulate an indoor PM dispersion from non-filtering air conditioner well.