In laboratory experiments, we investigated two task/ambient conditioning systems with air supplied from desk-mounted air outlets to efficiently ventilate the breathing zone of heated manikins seated at desks. In most experiments, the task conditioning systems provided outside air while a conventional ventilation system provided additional space cooling but no outside air. Air change effectiveness (i.e., exhaust air age divided by age of air at the manikin's face) was measured with a tracer gas step-up procedure. Other tracer gases simulated the release of pollutants from nearby occupants and from the floor covering, and the associated pollutant removal efficiencies (i.e., exhaust air concentrations divided by concentrations at manikin's face) were calculated. High values of air change effectiveness (~ 1.3 to 1.9) and high values of pollutant removal efficiency (~ 1.2 to 1.6) were measured when these task conditioning systems supplied 100% outdoor air at a flow rate of 7 to 9 L s-1 per occupant. Air change effectiveness was reasonably well correlated with the pollutant removal efficiency. Overall, the experimental data suggest that these task/ambient conditioning systems can be used to improve ventilation and air quality or to save energy while maintaining a typical level of IAQ at the breathing zone.
BT - Indoor Air '99 Conference, August 8-13, 1999 C2 - LBNL-42700 CY - Edinburgh, Scotland DA - 08/1999 LA - eng N2 -In laboratory experiments, we investigated two task/ambient conditioning systems with air supplied from desk-mounted air outlets to efficiently ventilate the breathing zone of heated manikins seated at desks. In most experiments, the task conditioning systems provided outside air while a conventional ventilation system provided additional space cooling but no outside air. Air change effectiveness (i.e., exhaust air age divided by age of air at the manikin's face) was measured with a tracer gas step-up procedure. Other tracer gases simulated the release of pollutants from nearby occupants and from the floor covering, and the associated pollutant removal efficiencies (i.e., exhaust air concentrations divided by concentrations at manikin's face) were calculated. High values of air change effectiveness (~ 1.3 to 1.9) and high values of pollutant removal efficiency (~ 1.2 to 1.6) were measured when these task conditioning systems supplied 100% outdoor air at a flow rate of 7 to 9 L s-1 per occupant. Air change effectiveness was reasonably well correlated with the pollutant removal efficiency. Overall, the experimental data suggest that these task/ambient conditioning systems can be used to improve ventilation and air quality or to save energy while maintaining a typical level of IAQ at the breathing zone.
NV - 4 PB - Construction Research Communications, Ltd., London PP - Edinburgh, Scotland PY - 1999 SP - 273 EP - 281 T2 - Indoor Air '99 Conference, August 8-13, 1999 T3 - Indoor Air '99 Conference, August 8-13, 1999 TI - Ventilation Efficiencies of Desk-Mounted Task/Ambient Conditioning Systems VL - 9 ER -