[Bldg-sim] How have you approached... (UNCLASSIFIED)

Shaun Martin smartin at shaunmartinconsulting.com
Wed Jul 20 09:20:25 PDT 2011


Hi Nick,
 
To keep it simple, I would just derate the schedules, your 10/15% reduction
but on an hourly basis (ie one or more hours are moved to 0%/setback) and
apply the RESET-PRIORITY and MIN-RESET-FLOW keywords.  I think averaging it
out beforehand and explaining as part of your modelling methodology in your
report would take less time and be easier to explain.  I would start with a
small test model, to make sure you have the right percentages. 
 
Shaun
 

Shaun Martin LEED AP

Principal

Shaun Martin Consulting

Suite 200 - 420 West Hastings Street

Vancouver BC   V6B 1L1

604-789-1095

 <blocked::mailto:smartin at shaunmartinconsulting.com>
smartin at shaunmartinconsulting.com

member CAGBC, ASHRAE


  _____  

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Nick Caton
Sent: Wednesday, July 20, 2011 8:45 AM
To: James Hansen; Eurek, John S NWO; David Eldridge;
bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] How have you approached... (UNCLASSIFIED)



Thanks so much for the suggestions! 

 

I myself have tread the "extensive, realistic fractional/thermostat
scheduling" path before under similar circumstances.  Upon facing a VERY
large project, where the amount of explicit scheduling required for that
approach is compounded by the sheer quantity and variety of occupied spaces
benefiting from this relay setup, I am challenged with brainstorming any
acceptable (by LEED reviewer) means of approximating the same
behavior/savings by simplifying the problem.

 

Here are some alternative ideas we've come up with so far  - I would very
much appreciate others' thoughts on these, or any further related LEED/USGBC
experiences to share as well:

1.       90.1 already prescribes how we quantify the savings of occupancy
sensors for installed lighting  (10 or 15% flat deduction on the LPD).
Rather than define & justify the quantity and timing of unoccupied hours
between varying space types (murky waters at best), one could instead reduce
the loads incident on the affected systems by the same percentage.  This
might be accomplished by applying this 10/15% deduction to the affected
spaces' fractional load schedules (occupancy, equipment & lighting).  One
would need to tread carefully to avoid "double-dipping" on any spaces
already claiming a LPD deduction for occupancy sensors.  Baseline model's
schedules would remain unaffected and would be documented alongside the
modified ones to illustrate the difference. 

2.       (Simpler to model, but requiring slightly more documentation):
Let's say a hospital has an annual average of 85% occupancy for all its
patient rooms.  Treating every other room normally, select a representative
sampling (considering envelope loads) of 15% of the patient rooms.  Model
those selected rooms as "empty" (set people, lights and equipment loads = 0)
but still conditioned to maintain the thermostat setpoint (against loads
incident from the envelope & neighboring spaces). Apply the 0% minimum
turndown behavior to those "empty" rooms only.  Baseline model would receive
identical treatments, excepting the 0% turndown behavior.  Documentation
would include illustrating which zones were sampled against the others, and
justification for the net annual "occupancy rate" used for each space type.

 

I have mixed feelings - obviously any simplification of the problem has the
potential to under/overstate the savings that might be found with a more
exhaustive scheduling approach, but may result in as good or even a better
estimation provided with solid documentation and execution.  Does anyone
think the above approaches could work well, or have any suggestions to
refine the strategies?  

 

Thanks again!

 

~Nick

 

 

cid:489575314 at 22072009-0ABB

 

NICK CATON, P.E.

SENIOR ENGINEER

 

Smith & Boucher Engineers

25501 west valley parkway, suite 200

olathe, ks 66061

direct 913.344.0036

fax 913.345.0617

www.smithboucher.com 

 

-----Original Message-----
From: James Hansen [mailto:JHANSEN at ghtltd.com] 
Sent: Wednesday, July 20, 2011 8:40 AM
To: Eurek, John S NWO; Nick Caton; bldg-sim at lists.onebuilding.org
Subject: RE: [Bldg-sim] How have you approached... (UNCLASSIFIED)

 

I agree with John, I've done this on a model before and its painful.
Assuming there are 10 hours in a work day, I set up 10 different occupancy
and lighting schedules, each schedule being essentially identical except for
a different hour of zero occupancy / lighting.  I then applied these 10
schedules to the different office zones on a floor so that specific areas
were vacant from 8am-9am, some vacant from 9am-10am, etc.  And then for my
system, I assumed relatively consistent 10% non-occupied conditions and
reduced the OA at the system level accordingly.  If your non-occupied
conditions are more drastic (30%), obviously you can set up your schedules
differently.

 

However, if your primary air is also cooling (and not some sort of DOAS
chilled water VAV box), then you are going to also have to specify 10
separate thermostat schedules (really 20 with heating and cooling) so that
the rooms do not have unmet load hours.  I'm assuming you go into setback
mode when the offices are unoccupied.

 

However, this was under v2.0, so that was a long time ago and reviewers were
not as critical in their reviews.

 

GHT Limited

James Hansen, P.E., LEED AP

Senior Associate

1010 N. Glebe Road, Suite 200

Arlington, VA  22201-4749

703-243-1200 (office)

703-338-5754 (cell)

703-276-1376 (fax)

www.ghtltd.com

 

-----Original Message-----

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Eurek, John S
NWO

Sent: Wednesday, July 20, 2011 9:31 AM

To: Nick Caton; bldg-sim at lists.onebuilding.org

Subject: Re: [Bldg-sim] How have you approached... (UNCLASSIFIED)

 

Classification: UNCLASSIFIED

Caveats: NONE

 

Nick,

 

I would do it with schedules.  This would be the long method.

 

I have the same controls and have not got around to model it.  I would also

make many schedules.  A different schedule for occupancy, lights, equipment,

ect.  Also if this applies to a lot of rooms, you'd likely make multiple

schedules, one assuming that the room is empty from 9~10 another room empty

from 2~3.  (The inverse for meeting rooms, if you have multiple meeting

rooms, not all meetings will happen at the same time.)

 

 

"Is Freedom a small price to pay to stop Global Warming?"

 

John Eurek PE, LEED AP

Mechanical Engineer,

 

-----Original Message-----

From: bldg-sim-bounces at lists.onebuilding.org

[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Nick Caton

Sent: Tuesday, July 19, 2011 3:59 PM

To: bldg-sim at lists.onebuilding.org

Subject: [Bldg-sim] How have you approached...

 

I have a precedent question for everyone... this is not a "how to"
procedural

question for any particular software, but to simply feel out what has worked

for others in the past:

 

 

 

Here's a quick description of the situation at-hand:  a VAV terminal unit

with a "normal" minimum damper position (say, 30%) is tied by relay to the

space occupancy sensor, which also controls the lights.  Upon sensing space

vacancy, the minimum airflow damper position is reset to 0% (airflow is

permitted to stop, provided thermostat temperature set point is satisfied).

Upon sensing occupancy, the preset minimum damper position is restored.

 

 

 

For LEED/USGBC-reviewed energy models, can anyone relate success in modeling

this or a similar energy-saving behavior in the proposed model, distinct
from

the baseline?  If so, what approach did you use to model this behavior
and/or

quantify the energy savings? 

 

 

 

I was discussing the possibilities with some colleagues and have a few ideas

for approaches that might all be justifiable, ranging from simple (and
quick)

to complex (and time-consuming).  

 

 

 

There are likely multiple "right" answers here, but I am hoping to identify

some precedent to understand what we can anticipate the LEED reviewership

will accept.  

 

 

 

Thanks in advance!

 

 

 

~Nick

 

 

 

cid:489575314 at 22072009-0ABB

 

 

 

NICK CATON, P.E.

 

SENIOR ENGINEER

 

 

 

Smith & Boucher Engineers

 

25501 west valley parkway, suite 200

 

olathe, ks 66061

 

direct 913.344.0036

 

fax 913.345.0617

 

www.smithboucher.com 

 

 

 

 

Classification: UNCLASSIFIED

Caveats: NONE

 

 

_______________________________________________

Bldg-sim mailing list

http://lists.onebuilding.org/listinfo.cgi/bldg-sim-onebuilding.org

To unsubscribe from this mailing list send  a blank message to
BLDG-SIM-UNSUBSCRIBE at ONEBUILDING.ORG

 

 

The information contained in this communication is confidential, may be
privileged, and is intended only for the use of the addressee.  It is the
property of GHT Limited.  Unauthorized use, disclosure or copying of this
communication or any part thereof is strictly prohibited and may be
unlawful.  If you have received this communication in error, please notify
me immediately by return e-mail or by e-mail to ght at ghtltd.com, and destroy
this communication and all copies thereof, including all attachments.  Thank
you.

 

 

 

 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/bldg-sim-onebuilding.org/attachments/20110720/02cf3e83/attachment-0002.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/jpeg
Size: 1459 bytes
Desc: not available
URL: <http://lists.onebuilding.org/pipermail/bldg-sim-onebuilding.org/attachments/20110720/02cf3e83/attachment-0002.jpeg>


More information about the Bldg-sim mailing list