Room air distribution and cooling load of hybrid air conditioning system utilizing natural ventilation in an ofice.

The characteristics of a hybrid air-conditioning system, utilizing natural and mechanical ventilation, is investigated in an office setting. The characteristics of the indoor environment are examined with CFD(Computational fluid Dynamics) simulation under various conditions of incoming outdoor air. The control of the room air conditioning system (VAY system) is included in the calculation through changing the supply air volume to keep the task zone's temperature at a target temperature. When the temperature of the inflow outdoor air rises, the inflow jet flows deeper into the room and mixes well with the indoor air. A vertical temperature gradient appears at the task zone with the rise in the incoming outdoor air temperature. The distribution of the age of air is under the strong influence of flow fields. The cooling load of the mechanical AC system increases with the increase of the outdoor air temperature and the decrease of the incoming outdoor air volume. From the viewpoint of energy conservation, the window opening (vertical width of the opening) should be made larger for ease of outdoor air intake.