Description

CO₂-based demand-controlled ventilation (DCV), when properly applied in spaces where occupancies vary below design occupancy, can reduce unnecessary overventilation while implementing target per-person ventilation rates. A recent interpretation of ANSI/ASHRAE Standard 62-1989, Interpretation IC 62-1989-27, has affirmed that carbon dioxide (CO₂)-based demand-controlled ventilation (DCV) systems can use CO₂ as an occupancy indicator to modulate ventilation below the maximum total outdoor air intake rate while still maintaining the required ventilation rate per person, provided that certain conditions are met.

This paper, co-written by the author of the interpretation, provides guidelines on the application of CO₂-based DCV. In addition, a method is presented that allows reasonable estimates of the actual ventilation rate per person being effectively delivered to the space, based on comparing predicted CO₂ ventilation levels with CO₂ levels logged in an occupied space. Finally, a model is presented to evaluate various CO₂-based DCV strategies to predict their delivery of target per-person ventilation rates within the lag times required by the standard. 

Units: Dual 

Citation: Symposium, ASHRAE Transactions, 1998, Vol. 104, Part 2, Toronto, ON

Product Details

Published:

1998

Number of Pages:

13

File Size:

1 file , 610 KB

Product Code(s):

D-7762