Description

The feasibility of controlling ventilation rates using occupant-generated carbon dioxide (CO₂) as the control index has been examined in a large high-rise office building with a constant-volume heating, ventilating, and air-conditioning (HVAC) system. Daily CO₂ concentration profiles throughout the building and air change rates, using sulphur hexafluoride (SF₆) as a tracer gas, were measured for several outdoor air supply rates. Of particular interest was how well the CO₂ concentrations measured in the central ventilation system’s return air plenum represented the average CO₂ concentration behaviour in the building as a whole, CO₂ concentration profiles were also measured on individual floor spaces in the building to determine the range of variability in the concentration behaviour in occupied zones. The influence of fresh air rates on the speed of mixing of the tracer gas (surrogate contaminants) was also examined. The practicability of using CO₂ as an active tracer gas to measure air change rates was also investigated. The results are discussed.

KEYWORDS: air change rate, carbon dioxide, content, multistorey buildings, offices, controls, occupiers, constant volume air conditioning, sulphur hexafluoride, tracers, measuring, supply air, air distribution, mixing

Citation: Symposium, ASHRAE Trans. 1994, Vol.100, Part 2

Product Details

Published:

1994

File Size:

1 file , 1.2 MB

Product Code(s):

D-17700