Hi All,
I'm modeling a system with DCV set to "DCV-RETURN-SENSOR." The help file says: "The program calculates the OA minimum requirement and sets the minimum damper position hourly based upon the sum of the ZONE requirements. Each zone OA requirement is calculated based upon the hourly maximum of either OA-CFM/PER (times the NUMBER-OF-PEOPLE adjusted by the hourly PEOPLE-SCHEDULE) or a minimum OA ventilation rate."

However, when I look at the hourly report for the zone, "Hourly zone OA CFM requirement for DCV calculation (cfm)" (Var 100), the CFM does not increase for high occupancy hours. My hand calculations show that when I multiply the OA-CFM/PER by the hourly occupancy, it should exceed the minimum OA ventilation rate for the zone (which I specified using OA-FLOW/AREA.)

I have set the zone minimum flow ratios to "DCV-RESET-UP/DOWN" and the zone minimum flow is increasing according to the occupancy.

Why is the zone OA CFM requirement not increasing with occupancy? Any thoughts are appreciated.

Thanks very much.

Kind regards,
Molly

Molly Curtz