Ventilation efficiencies of task/ambient conditioning systems with desk-mounted air supplies.

In laboratory experiments, we investigated the ability of two task/ambient conditioningsystems with air supplied from desk-mounted air outlets to efficiently ventilate the breathingzone of heated manikins seated at desks. In most experiments, the task conditioning systemsprovided 100% outside air while a conventional ventilation system provided additional spacecooling but no outside air. Air change effectiveness (i.e., exhaust air age divided by age of airat the manikins face) was measured. Tracer gases simulated the release of pollutants fromnearby occupants and from the floor covering, and the associated pollutant removalefficiencies (i.e., exhaust air concentrations divided by concentrations at manikins face) werealso measured. High values of air change effectiveness (- 1.3 to 1.9) and high values ofpollutant removal efficiency (- 1.2 to 1.6) were measured when these task conditioningsystems supplied 100/0 outdoor air at a flow rate of 7 to 10 L/s per occupant.