eQuesters,
Some of you might recall the e-mails (below, but probably not necessary
to re-read) from early August. Since then, my problem has simplified, but
the solution is not so clear to me.
Basically, I have exhaust fans for a particular shell located in a
"core" zone made of restrooms and an electrical room. No supply or return
air devices exist in this core zone. Rather, the core zone gets its air
from transfer through doorways (and maybe one passive transfer duct) from a
large open office zone. (Note: Insofar as the core zone does not have an
HVAC system, per se, Vikram's excellent previous answer seems inapplicable
now.)
Here are the questions:
1. When using eQuest, shall I deem the core zone "unconditioned" or
"plenum" or "conditioned"?
2. What HVAC system, if any, shall I tell eQuest that the core zone belongs
to? Is there even a way, if appropriate, to tell eQuest that a zone does
not belong to an HVAC system?
3. How can I explain to eQuest that the office zone exhausts (passively) to
the core zone, which then exhausts via fans to the outside?
Thank you all in advance for your help - and to Vikram for his previous
response.
Lars Fetzek, EI
Lars,
Not sure if this is what you're looking to do. I haven't tried this for
a chain of more than two zones, but you can specify the outside air
coming from a particular zone in eQUEST using the "OA-FROM-SYSTEM"
keyword. You have to be careful with this to define the OA system before
the system it feeds (i.e. if system 1 has an OA-FROM system2, but system
2 has not been defined yet in the INP file, you will get an error.
Another thing to watch out for is that when you use the OA-FROM, I don't
think eQUEST calculates the cooling effect of the ventilation air. You
might have to trick the program into accounting for that using an
internal energy source (process) with a negative value. This is easier
with a constant volume OA supply, but if you really want to you could
write a schedule for the VAV supply - it's pretty tricky.
Vikram Sami, LEED AP
Direct Phone 404-253-1466 | Direct Fax 404-253-1366
LORD, AECK & SARGENT ARCHITECTURE
From:
[mailto:
Fetzek
Sent: Monday, August 10, 2009 9:47 AM
To:
Subject: [Equest-users] Exhaust air routes
Hello,
The building floor that I am presently modeling has several
conditioned zones and two unconditioned zones. The conditioned zones
are various offices. The unconditioned zones are restrooms and an
electrical room. The conditioned zones exhaust to each other and,
ultimately, to the unconditioned zones via hallways, doorways, etc. The
unconditioned zones exhaust to the outside (via fans).
How can I explain to eQuest that, for example, conditioned zone A
exhausts to conditioned zone B? Also, how can I explain to eQuest that
conditioned zone D exhausts X% to the electrical room (and thus to
outdoor exhaust fans) and Y% to conditioned zone C?
In case it matters, the ceiling is open and the return ductwork
terminates in one spot. Accordingly, even return air must flow among
the conditioned zones.
Thanks, as always, for your helpful replies.
Lars Fetzek, EI
