This paper describes tests of thermal and ventilation performance of two relatively new occupant-controlled localized thermal distribution (also called task ventilation) systems. The first is a raised-floor distribution system providing air through grilles in the floor panels, and the second is a desk-mounted unit supplying conditioned air at desktop level. These systems have been tested in a mockup of a typical partitioned open-plan office, and the resulting temperature and air velocity distributions are reported for a variety of system and locally controlled conditions.
In an experimental facility, we studied the performance of a task ventilation system designed for use in office buildings. With this system, occupants can adjust the flow rate and direction of air supplied to their work space through four floor-mounted supply grills. Air typically exits the ventilated space through ceiling-mounted return grills. To study indoor air flow patterns, we measured the age of air at multiple indoor locations using the tracer gas stepup procedure.
What does the designer of a future energy-efficient building ask of the air flow specialist? - Static predictions of air flow patterns and optimization of thermal comfort and indoor air quality at design conditions will not be enough for him. The paper suggests that time-dependent air flow simulation is imperative to respond to tomorrows design needs. Different physical timescales for air flow patterns in spaces will be discussed. Heat capacity by components, different types of heat transfer, varying occupancy, control inputs etc. give rise to disparate time scales.
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