Investigation of design concept and basic performance of task air conditioning system for wide use

Authors have developed a practical Task and Ambient Air Conditioning system which could respond to layout change of office. The system supplies air from a task unit installed in a partition, using pressure difference between underfloor and office room with a pressurization type under floor air-conditioning system as driving force. Performance experiments of the developed system in an early stage have been conducted using a mock-up to know a quantity required for air supply of a task unit. It was found that 25-35 CMH of supply air volume was obtained as maximum when pressure difference was 10-15 Pa, and it could be reduced to 5-8 CMH as minimum by adjusting the slide shutter for air volume control. In addition to that, by operating guide vanes for airflow direction adjustment, it was possible to control airflow direction from 0 to 45 degrees, and air velocity at a seat position was 0.3-0.4 m/s then. Field performance experiments of the system in a real office was also conducted with a thermal mannequin. It was confirmed that controllability of supply air volume and airflow direction of the system. Equivalent temperature (Teq) of each human body part was almost 28°C except head part that received direct air flow from task unit. It was confirmed that Teq of head part was 25°C. Results of questionnaire surveys against workers using task units in the office showed that almost all of votes were thermally comfort side.