A task/ambient air-conditioning system with natural ventilation was installed in a high-rise office buildingin Osaka, Japan. This paper will report the results of the field measurements of indoor thermalenvironment and natural ventilation opening performances. From the thermal environmental aspect,the office is properly divided into working task zones and a general ambient zone so as to ensureboth occupants comfort and energy savings. Task air-conditioning is for satisfying individual thermalpreferences by using floor outlets.
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.