Carbon Dioxide Concentrations and Minimum Air Change Rates in a High-Rise Office Building

Abstract

The carbon dioxide concentration patterns in a large, high-rise, office building in Ottawa were examined experimentally using an automated data acquisition system. Daily CO₂ concentration profiles throughout the building and air change rates, using SF₆ as a tracer gas, were measured at minimum outdoor air supply rates during much of a heating season. Of particular interest was how well mixed the indoor air was and how well the CO₂ concentrations that were measured in the central ventilation system's return air plenum represented the average CO₂ concentration behaviour in the building as a whole. CO ₂ concen tration profiles were also measured on individual floor spaces in the building to determine the range of variability in the concentration behaviour. The mea surement results are presented and discussed in the context of demand-con trolled ventilation.

Keywords

Carbon dioxide Ventilation Air change rate Office building Tracer gas CO2-based demand control

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References

ASHRAE Standard 62-1989: Ventilation for Acceptable Indoor Air Quality. Atlanta, American Society of Heating, Refrigerating and Air-Conditioning Engineers.

Shaw CY , Magee RJ , Shirtliffe CJ , Unligil H. : Indoor Air Quality Assessment in an Office-Library Building. Part 1. Test Methods. ASHRAE Trans 1991;97:129-135.