OA From System Question

3 posts / 0 new
Last post

Morning:

I am trying to model a chilled beam system as induction units. The primary air
is supplied by an ERU. I set the outside air to 0 on the chilled beams HVAC
systems tab.

In the chilled beam zone tab I set the outside air to the primary CFM and the
overall CFM to the induced air flow.

Per the eQuest help menu, "The sum of the OA requirements for all SYSTEMs that
reference an OA-FROM-SYSTEM is used to set the referenced OA-FROM-SYSTEM value
for MIN-OUTSIDE-AIR, SUPPLY-FLOW as well as adjust the referenced
OA-FROM-SYSTEM directly served ZONE maximum and minimum flows for both heating
and cooling."

But per my hourly reports, the ERU is not supplying the necessary amount of
primary air and in the summer the ERU flow drops to .01 CFM.

Attached are the project files. Any ideas?

Thank you,

Paul Diglio, CEM, CBCP

Paul Diglio's picture
Offline
Joined: 2011-09-30
Reputation: 400

I restored default to the other zonal level OA quantities (OA per
person, etc), and kept the OA CFM in that you had listed, and I'm
showing OA CFM for ERU-1. But I only had a few minutes, so you might
want to double check.

GHT Limited
James Hansen, P.E., LEED AP

James Hansen's picture
Offline
Joined: 2011-09-30
Reputation: 200

Thanks James. I tried restoring the defaults you suggested, but the ERU hourly
report is still showing only 1/3 of the required primary air for the chilled
beams and it still drops to .01 CFM during the summer.

Paul Diglio, CEM, CBCP

Paul Diglio's picture
Offline
Joined: 2011-09-30
Reputation: 400