# [BLDG-SIM] Variable Speed Exhaust

Jeff Haberl jhaberl at esl.tamu.edu
Fri Jan 3 13:34:31 PST 2003

```Hello:

Can't help but jump in when someone refers to me as a "lofty scholar".
Actually, my lab office is in the basement (chamber of doom?).

Not a bad answer from John Aulbach. I agree that Jeff Hirsh would be the one
to answer questions about PowerDOE. I'm also a

"barefoot" DOE-2 user who writes his own BDL. Obviously, at some point your
going to need to dig into the manual and see what

each fan in your system is and how that compares to what you want. I'm not
sure what PowerDOE does.

It is my understanding that DOE-2 can be used to simulate "demand"
ventilation, by specifying the CFM/PERSON, which is really

acting like a perfect CO2 controller. The fans and the amount of ventilation
would need to be described by the user. Most likely,

looking at some of the hourly outputs for a given day would be helpful in
your case.

Jeff

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++++++++++++++++++++++++++++++

I'm trying to simulate a variable speed exhaust fan of the type manufactured
by Melink.  Supposedly, the exhaust will turn on as required based on room
temperature and on smoke/CO2 levels. I was thinking to maybe model just a
CO2 demand control ventilation system using a minimum outside air schedule.
I appreciate your help. I'm still learning PowerDOE, and learning it on my
own. Do you know of any colleges that might do distance learning for
simulation programs of this type? Again, thanks for any help.

Sincerely,

JP Carioto

8=!   8=)  :=)   8=)   ;=)   8=)   8=(   8=)   8=()   8=)   8=|   8=)   :=')
8=)   8=)   8=?

Jeff S. Haberl, Ph.D., P.E.............................jhaberl at esl.tamu.edu
Associate Professor....................................Office Ph:
979-845-6507
Department of Architecture...........................Lab Ph: 979-845-6065
Energy Systems Laboratory...........................FAX: 979-862-2457
Texas A&M University..................................77843-3581
College Station, Texas, USA...........................URL: www-esl.tamu.edu

8=/   8=)  :=)   8=)  ;=)   8=)   8=()   8=)   :=)   8=)   8=!   8=)   8=?
8=)   8=)   8=0

-----Original Message-----
From: postman at gard.com [mailto:postman at gard.com]On Behalf Of Aulbach, John
Sent: Friday, January 03, 2003 1:55 PM
To: BLDG-SIM at gard.com
Subject: [BLDG-SIM] Variable Speed Exhaust

Got an idea, but it needs further research. I run DOE-2.1E, and PoweDOE is
2.2, but everything in my version carries forward in intent and philosophy
into 2.2.

Chose a SYSTEM (or whatever PowerDOE calls a SYSTEM) that is a VAV system
that allows a RETURN-AIR fan. Make that SYSTEM 100% outside air. Therefore
both SUPPLY and RETURN FANS are variable flow, and the RETURN FAN
essentially becomes an EXHAUST or RELIEF fan.

You then need to tell the fans what controls their speed, which could be
temperature, or a schedule for usage (occupied/unoccupied, etc). If your
kitchen SUPPLY fan actually exists, it will have a variable flow over its
coils. If all air is entrained into the space (NO SUPPLY FAN), simply set
the KW/CFM to zero and any coils it contains to ZERO btu capacity to negate
any energy usage from a SUPPLY FAN.

By the way, I believe PowerDOE will give you, in the raw DOE2 reports, all
fans individually by SYSTEM consumption. The RETURN FAN will be your EXHAUST
FAN.

I believe this will give you a variable speed exhaust. I would like my
colleagues in DOE2 cyberspace to confirm my suspicions. Jeff Hirsch, Jeff
Haberl, and other lofty scholars, do you think this will give this gentleman
his answer?

-----Original Message-----
From: HermesPropylaios at aol.com [ mailto:HermesPropylaios at aol.com
<mailto:HermesPropylaios at aol.com> ]
Sent: Friday, January 03, 2003 11:03 AM
To: BLDG-SIM at GARD.COM
Subject: [BLDG-SIM] Variable Speed Exhaust

Hi all:
I'm trying to model a variable speed exhaust fan in a kitchen for a large
hotel in PowerDOE.  I'm not sure how to go about it.  If anyone could give
me some ideas, or if anyone has done this before, I would appreciate it.
Thank you.

John Carioto

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