FIELD STUDY ON TASK AIR CONDITIONING SYSTEM PERFORMANCE IN OFFICE BUILDING

There are many proposed variations of air distribution for Task and Ambient Air Conditioning system (TAC), however, most of them are pilot installations at office buildings. Authors have developed a practical Task and Ambient Air Conditioning system which could respond to layout change of office. The authors have conducted investigation on various performances of the developed TAC in a real building where the system has been set with pressurized type under floor air conditioning system extensively. When evaluating effects of the TAC, behavior of office workers that considered to affect the result, was monitored in detail. It was confirmed that correlation between moving distance and metabolic rates of office workers were quite high. When the office workers were allowed to freely control airflow of task unit, it was found that reduction of mental fatigue symptoms and the total vote rates of symptoms in comparison with the other cases. Vitality degree fall of the office workers was small for cases of ‘air diffuser of task unit was full open’ and ‘freely control of task airflow’. From these results, it was found that to allow office workers control volume and direction of task airflow was pretty much influenced on mental work load and maintain vitality of them under 28℃ room air temperature set point. In addition, in order to grasp the ventilation effectiveness of the TAC in the real office, ventilation effectiveness was measured by tracer gas. Compared to the other TAC systems tested before, the proposed TAC had equivalent performance. Also fresh air could be supplied to close proximity to breathing zone of occupants by adjusting the airflow direction of the TAC appropriately.