Hybrid air conditioning based on natural and mechanical ventilation in office buildings.

The performance of a hybrid air-conditioning system which utilises wind-induced cross ventilation is investigated. The characteristics of flow and temperature fields are examined using CFD simulation under various conditions of inflowing outdoor air i.e. air temperature, air exchange rate and width of the opening for cross ventilation. In this simulation, the room air controlling system (VAV system) which is used to keep the task zone at a target temperature is reproduced through changing the supply airflow rate of the air-conditioning system. Cooling load of the mechanical air-conditioning system is analysed based on the results of these simulations. When the inflaming outdoor air flows in the lower part of the room, it does not mix with the room air and cools the task zone well.