Hello,
I am modeling a VAV system and I am entering either Min-OA/person or Min-OA/area for each zone. I ran an hourly report and noticed that when I specify a minimum flow ratio the system flow rate will drop below the minimum OA rate.
Has anyone had this issue and is there a way to get the flow to stay above the ventilation requirement?
Thanks in advance,
Neil Patel, EIT, LEED AP BD+C
Neil,
There's not a hassle-free way to fix this. In order to avoid the behavior you're seeing, you can specify the min flow ratio for each zone at the zone level (rather than at the system level). In this case, you will need to manually verify that the zone OA requirement is less than the min flow ratio you input for each zone. If the zone OA requirement dictates the zone minimum flow, then leave the min flow ratio blank for that zone (to avoid reducing flow below the min OA requirement.)
The Advanced VAV Design Guide includes more guidance on using eQuest to model VAV system control sequences:
http://www.energydesignresources.com/resources/publications/design-guidelines/design-guidelines-advanced-variable-air-volume-(vav)-systems.aspx
Kind regards,
Molly Curtz