[Equest-users] Demand Controlled Ventilation and EA Credit 1

[ron lamarre]

Bill and James:

...the proposed would have the max number of people for only as many hours 
as submitted in the project narrative for FTE usage of the space, and a minimum 
number of people (or no one) for the remaining occupied-mode time....
 
Baseline = 100% of the occupancy for each space not required to have DCV.  
Reducing the occupancy (% of people) within the space to coincide with the FTE 
usage provides a reduced OA based on DCV control.  The OA per SF of the space 
remains the same in both cases.  The building's occupied/unoccupied schedules 
remain the same in both cases.
 
Example:
Baseline = Space occupied 7am to 7pm with 20 people (100% scheduled occupancy 
for all 12 hours)
Proposed DCV = Space occupied 7am to 9am with 20 people (100% scheduled 
occupancy for 2 hours) and 9am to 5pm with 2 people (10% scheduled occupancy 
for 8 hours) and 5pm to 7pm with 0 people (0% schedule occupancy for 2 hours): 
based on FTE usage of space.
 
Both models have the same building occupancy schedules 7am to 7pm.

I thought we were discussing DCV control and OA rates, which refers to spatial 
occupancy schedules; not building occupied/unoccupied schedules, so I don't know 
how we got onto the topic of building occupancy schedules.

Ron Lamarre, AIA, NCARB
Architect - LEED AP BD+C

Design  +  Energy Modeling + LEED Administration





________________________________
From: "Bishop, Bill" <wbishop at pathfinder-ea.com>
To: James Hansen <JHANSEN at ghtltd.com>; ron lamarre <lamarre_arch at yahoo.com>; 
equest-users <equest-users at lists.onebuilding.org>
Sent: Tue, July 27, 2010 2:32:07 PM
Subject: RE: [Equest-users] Demand Controlled Ventilation and EA Credit 1


Ron,
I’m with James on this one. I can see changing lighting or equipment schedules 
to capture ECMs but changing occupancy schedules makes no sense unless you’re 
modeling telecommuting or 4-day work week. You can capture DCV savings in eQUEST 
by selecting DCV as the Minimum OA Control Method for the system and having an 
occupancy schedule with a varying percentage (not 100%) during occupied hours. 
Using the same occupancy schedule, the model with DCV will heat/cool less OA air 
and show savings.
Regards,
Bill
 
WilliamBishop , PE, BEMP, LEED® 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
PSustainability – less is more.

________________________________

From:equest-users-bounces at lists.onebuilding.org 
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of James Hansen
Sent: Tuesday, July 27, 2010 2:23 PM
To: ron lamarre; equest-users
Subject: Re: [Equest-users] Demand Controlled Ventilation and EA Credit 1
 
“For the record, the occupancy schedule refers to the people present within the 
space.  For instance, a space within the baseline (not required by ASHRAE to 
have DCV) would have the max number of occupants for the entire occupied-mode 
schedule; however, the proposed would have the max number of people for only as 
many hours as submitted in the project narrative for FTE usage of the space, and 
a minimum number of people (or no one) for the remaining occupied-mode time.  
Thus we create an occupancy (people) schedule for the space.  During the 
unoccupied mode the fans would cycle as required with no people, no lighting 
(automatic shut off), acting on the heating & cooling loads.  We would 
not install DCV if the occupant loads didn't change during the occupied mode.”
 
Ron, please educate me if I’m reading your email wrong, but are you saying that 
your occupancy schedule in the proposed design does not match the baseline 
design? This is strictly prohibited in App G I thought… You can change schedules 
to take advantage of non-standard ECMs like DCV, and automatic lighting 
reductions for the use of occupancy sensors (in rooms NOT already required to 
have them by code). But having a conference room 100% occupied from 7am-6pm in 
the baseline model and only 100% occupied from 9am-noon in the proposed model is 
not a valid way to demonstrate savings from DCV, since there will be energy 
savings related to the people latent/sensible production that has nothing to do 
with DCV. Don’t you have to create a minimum outside air schedule to demonstrate 
DCV savings? If you have received credit for simply reducing the Occupancy 
Schedule in the proposed model, that is very interesting…
 
Thanks!
 
GHT Limited
James Hansen, PE, LEED AP
Senior Associate
1010 N. Glebe Rd, Suite 200
Arlington, VA  22201-4749
703-338-5754 (Cell)
703-243-1200 (Office)
703-276-1376 (Fax)
www.ghtltd.com
 
 
From:ron lamarre [mailto:lamarre_arch at yahoo.com] 
Sent: Tuesday, July 27, 2010 2:08 PM
To: James Hansen; equest-users
Subject: Re: [Equest-users] Demand Controlled Ventilation and EA Credit 1
 
Hi James:
 
For the record, the occupancy schedule refers to the people present within the 
space.  For instance, a space within the baseline (not required by ASHRAE to 
have DCV) would have the max number of occupants for the entire occupied-mode 
schedule; however, the proposed would have the max number of people for only as 
many hours as submitted in the project narrative for FTE usage of the space, and 
a minimum number of people (or no one) for the remaining occupied-mode time.  
Thus we create an occupancy (people) schedule for the space.  During the 
unoccupied mode the fans would cycle as required with no people, no lighting 
(automatic shut off), acting on the heating & cooling loads.  We would 
not install DCV if the occupant loads didn't change during the occupied mode.
 
We also use general lighting schedules that take advantage of installed 
occupancy sensors, and process load schedules that take advantage of Energy Star 
computers and monitiors.
 
The HVAC engineer decides the minimum design rate for each space to work 
(heating & cooling) if fully occupied with all the lights, process loads, and 
people during the occupied mode.  This is normally at or above the 62.1 and/or 
other code-required minimums (never below due to the LEED pre-requisite).  
Sharing the reduction schedules placed into eQuest with a template-narrative to 
support the reductions (based on ASHRAE 90.1, Energy Star, etc... %-reductions) 
has been accepted by LEED.
 
We utilize an integrated design team method, where the engineers and 
I review the models that I construct.  We also get peer reviews when we think 
it's necessary and/or when LEED throws us a curve.  We pay for our peer 
reviews.  I'm confident that anything we've submitted does not prove 
inconsistency within the review of EAc1.
 
Ron Lamarre, AIA, NCARB
Architect - LEED AP BD+C
 
Design  +  Energy Modeling + LEED Administration
 
 

________________________________

From:James Hansen <JHANSEN at ghtltd.com>
To: ron lamarre <lamarre_arch at yahoo.com>; Karen Walkerman 
<kwalkerman at gmail.com>; 

Sent: Tue, July 27, 2010 12:57:21 PM
Subject: RE: [Equest-users] Demand Controlled Ventilation and EA Credit 1
“Each model that I've done for LEED utilizes the same ventilation rates between 
the proposed and design; whether it was ASHRAE 62.1 or IMC 2003; however, the 
occupancy schedules changed in spaces where DCV was installed.”
 
Ron, that’s an interesting statement in itself – modifying occupancy schedules 
has an impact on the mechanical cooling (not just the cooling associated with 
reduced ventilation air), which isn’t really fair.  Was that approved by GBCI?  
If so, I guess it’s further proof that there is still a lot of inconsistency in 
the review of EAc1.  

 
Karen, I think your letter does a good job of requesting an official “ruling” 
from the USGBC.
 
GHT Limited
James Hansen, PE, LEED AP
Senior Associate
1010 N. Glebe Rd, Suite 200
Arlington, VA  22201-4749
703-338-5754 (Cell)
703-243-1200 (Office)
703-276-1376 (Fax)
www.ghtltd.com
 
 

________________________________

From:Karen Walkerman <kwalkerman at gmail.com>
To: equest-users <equest-users at lists.onebuilding.org>
Sent: Tue, July 27, 2010 12:10:27 PM
Subject: [Equest-users] Demand Controlled Ventilation and EA Credit 1
All,
 
below is a draft letter to the EA Credit 1 TAG chair.  I welcome any edits, or 
critiques, and if anyone would like to be a co-signer of the letter, please let 
me know.
 
Thanks,
 
--
Karen
 
 
It has come to our attention from a posting on the eQuest list-serve that a 
fellow energy-modeling professional has been asked to model proposed design and 
baseline design ventilation rates differently where the proposed design model 
utilizes demand controlled ventilation.  We have searched the ASHRAE 90.1 
documentation as well as the LEED reference documentation and consistently find 
the requirement that baseline ventilation rates be modeled the same as the 
proposed design, and that credit can be taken for demand controlled ventilation.
 
We understand that large energy savings can be gained from demand controlled 
ventilation and that in certain cases, 'gaming' of the system could result in 
abnormally high ventilation rates for the baseline design, while the DCV system 
keeps ventilation rates low in the proposed design, however, our main concern is 
that energy modelers are being made aware of changes to guidelines during the 
design review process.  At this stage, the energy modeler has already completed 
a significant amount of work in preparing the proposed and baseline design 
energy models, and all associated documentation.  Changing the baseline design 
ventilation rates requires re-modeling of the building and increases the 
likelihood that the project will have to challenge a 'rejected' result if the 
LEED reviewer is not satisfied with the energy modeler's response and modeling 
changes.
 
We feel that it may be time to develop modeling guidelines for demand controlled 
ventilation, and that these guidelines should be developed, released, and 
required in a similar fashion to the district energy guidelines published by 
LEED for NC 2.2  Furthermore, we feel that any changes made to EA Credit 1 
energy modeling guidelines should be made with adequate notice to the energy 
modeling community.
 
Thank you for your consideration on this issue,
 
--
Karen Walkerman
Second Law
 
 
 

________________________________

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