[Equest-users] Demand Controlled Ventilation

Victor Yeung Victor at invirosystems.ca
Wed Apr 28 10:59:53 PDT 2010


Otto,

 

Thanks for the reply.  The problem I see with dividing the total OA cfm
by the number of people and inputting that number into OA-FLOW/PER is
that this method doesn't address the space cfm requirement.  For
example, if the building is only 10% occupied at a particular hour, then
the OA supplied will be 10% occupant requirement and 10% of space
requirement, not 10% occupant and 100% area as it should be.

 

Victor

 

From: Otto Schwieterman [mailto:oschwieterman at fhai.com] 
Sent: April 28, 2010 1:44 PM
To: Victor Yeung
Subject: RE: [Equest-users] Demand Controlled Ventilation

 

Victor,

 

If you do not have DCV, you must specify the amount of CFM per room (or
per SF) because if you simply put CFM/person, you are essentially using
DCV due to the occupancy change in the schedules. 

 

If you want to utilize DCV, I would calculate the total outside air CFM
required and divide the total by the number of people and input that
number into OA-FLOW/PER.

 

Otto

 

From: Victor Yeung [mailto:Victor at invirosystems.ca] 
Sent: Wednesday, April 28, 2010 12:30 PM
To: Bishop, Bill; Rob Hudson
Cc: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] Demand Controlled Ventilation

 

Hello all,

 

I also have a similar question related to minimum OA settings for DCV,
particularly with OA-FLOW/PER and OA-FLOW/AREA.  Say I am using ASHRAE
62.1 for my OA rates, there are minimum requirements for cfm/person and
cfm/area.  However, the way eQuest calculates min zone OA is by taking
the higher value of either OA-FLOW/PER or OA-FLOW/AREA, not the combine
total.  To correctly model the OA requirement, I have to calculate the
combine OA rate (i.e. {[cfm/per * max # of person] + [cfm/area * floor
area] } / floor area) and input that value in OA-FLOW/AREA.  Now, the
problem comes in when we include DCV into the model, at which eQuest
cannot calculate the savings because the OA-FLOW/PER value is not
entered.  I would greatly appreciate it if anyone can clarify this.

 

VICTOR YEUNG, BASc, LEED(r) AP

EIT - LEED(r)/Sustainable Development

victor at invirosystems.ca <mailto:victor at invirosystems..ca> 

 

 

From: Bishop, Bill [mailto:wbishop at pathfinder-ea.com] 
Sent: April 28, 2010 11:16 AM
To: Rob Hudson
Cc: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] Demand Controlled Ventilation

 

Rob,

 

You need to set up an hourly report. See attached.

 

Bill

 

________________________________

From: Rob Hudson [mailto:rdh4176 at gmail.com] 
Sent: Wednesday, April 28, 2010 11:06 AM
To: Bishop, Bill
Cc: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] Demand Controlled Ventilation

 

How can i tell if the system is using a lower OA CFM during the less
occupied times? 

On Wed, Apr 28, 2010 at 10:43 AM, Bishop, Bill
<wbishop at pathfinder-ea.com> wrote:

Rob,

 

I recently modeled DCV successfully for the first time. (I showed
savings anyway.) You need to enter zone-level OA as OA-FLOW/PER and/or
OA-FLOW/AREA. The OA flow/per (person) is what will get you the savings,
based on your occupancy schedule(s). I also created a MIN-AIR-SCH,
coinciding with the fan schedule, set to zero when fan is off and -999
when fan is on.

 

Regards,

Bill

 

William Bishop, EIT, BEMP, LEED(r) AP | Pathfinder Engineers &
Architects LLP

Mechanical Engineer

 

134 South Fitzhugh Street
Rochester, NY 14608
T: (585) 325-6004 Ext. 114
F: (585) 325-6005

wbishop at pathfinder-ea.com

www..pathfinder-ea.com <http://www.pathfinder-ea.com> 

P Please strive to live sustainably.

________________________________

From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Rob
Hudson
Sent: Wednesday, April 28, 2010 9:55 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Demand Controlled Ventilation

 

I am having some trouble with setting up DCV in my model.  if i select
DCV in Zone Sensors for the Min OA Control Method and a min outside Air
Ratio, do i need any Zone level OA inputs?
Any help or insight as to what inputs are necessary for DCV would be
great!

-- 
Rob Hudson




-- 
Rob Hudson

________________________________________________________________________
________________
Fanning/Howey Associates, Inc. intends to send this transmission
(including any attachments) only to the
designated individual or entity.   If you received this message in
error, please notify the sender by replying
to the electronic mail (if electronic) or by telephone at the number
indicated on this document.
Fanning/Howey Associates, Inc. has taken reasonable precautions to
ensure no viruses are present in the
electronic mail.  Fanning/Howey Associates, Inc., will not accept
responsibility for any loss or damage arising
from the use of this electronic mail or attachments. Use, disclosure,
dissemination, distribution, or reproduction
of this message by unintended recipients is not authorized and maybe
unlawful.   Any information included in
this transmission that is not related to contracts with our
authorization, verbal or written, by Fanning/Howey
Associates, Inc. may not be covered by our professional liability
insurance.. 
 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20100428/8ec62998/attachment.htm>


More information about the Equest-users mailing list