CFD ANALYSIS OF AIRFLOW CHARACTERISTICS IN OFFICE ROOM WITH TASK AIR-CONDITIONING AND NATURAL VENTILATION

The performance of indoor airflow for the office room with the hybrid air-conditioning system has been investigated by means of CFD analysis. The hybrid air-conditioning system is composed of under floor air supply outlets for task zone and the natural ventilation openings for ambient zone. The measured data (Kotani et al. 2006) at the office room in existence was used as the boundary condition of the flow rate of each natural ventilation opening and task flow outlets for CFD. To investigate the influence of location of the natural ventilation opening, two models with different location of openings for natural ventilation were made; one is the case with openings for natural ventilation under the ceiling (“ceiling-model”; Lim et al. 2007) and the other is the case with openings for natural ventilation near the window side (“counter-model”). It was made clear that the ceiling-model can supply the fresh air more widely to the occupancy zone than counter-model. Moreover, CFD analysis using ceiling-model was conducted to investigate the influence of the outdoor air condition (wind direction, wind velocity and outdoor temperature). As the results, the distribution of fresh air under the north wind is more uniform than that of the west wind. Under the west wind, SVE4 of natural ventilation openings is highest in the west-side zone