[BLDG-SIM] Process Loads and LEED

Dahlstrom, Aaron ADahlstrom at AKF-ENG.com
Tue Mar 6 12:05:35 PST 2007


p182 of the reference guide offers further guidance:
 
"Process energy cost shall be equal to at least 25% of the baseline
building performance."
 
Aaron Dahlstrom
AKF Engineers, LLP

-----Original Message-----
From: BLDG-SIM at gard.com [mailto:BLDG-SIM at gard.com] On Behalf Of Brian
Thornton
Sent: Tuesday, March 06, 2007 2:59 PM
To: BLDG-SIM at gard.com
Subject: [BLDG-SIM] Process Loads and LEED



The interpretation of what "default" means is the key.  Since the second
provision says that baseline and proposed process loads shall be
identical, if the design process loads are 60%, than the baseline should
be 60%, unless you ignore the second provision.  

 

If the interpretation of the "default" is that baseline is always 25%*
even if the design process is greater than 25%, than the two cited
paragraphs are in contradiction in many cases. (*except for the special
case of documented process usage less than 25%)

 

I'm not a lawyer, but it seems these need to reconciled so both
paragraphs make sense, or are changed. 

 

My guess/hope is that the USGBC did not intend to exclude all high
process load buildings from showing savings under EAc1. 

 

Brian

 

Thornton Energy Consulting

p. 503-231-6600 f. 503-231-3555

thorntonenergy at comcast.net

 


  _____  


From: BLDG-SIM at gard.com [mailto:BLDG-SIM at gard.com] On Behalf Of gail
Sent: Tuesday, March 06, 2007 10:47 AM
To: BLDG-SIM at gard.com
Subject: [BLDG-SIM] Process Loads and LEED

 

The exact wording of the LEED v2.2 requirements may be helpful in moving
this discussion forward.  Per LEED EAc1 requirements:

"The default process energy cost (must) be 25% of the total energy cost
for the Baseline building.  For buildings where the process energy cost
is less than 25% of the baseline building energy cost, the LEED
submittal must include supporting documentation substantiating that
process energy inputs are appropriate. "
...
"For EA Credit 1, process loads shall be identical for both the Baseline
building performance rating and for the Proposed building performance
rating.  However, project teams may follow the Exceptional Calculation
Method (ASHRAE 90.1-2004 G2.5) to document measures that reduce process
loads.  Documentation of process load energy savings shall include a
list of the assumptions made for both the base and proposed design, and
theoretical or empirical information supporting these assumptions. "

Buildings with 60% process energy cost probably will likely be
negatively impacted by these modeling requirements (it is probable that
these buildings will have a tougher time showing substantial Percentage
Energy Improvement than buildings having only 25% process loads).
However, if the project can demonstrate that energy improvements have
been made to the process energy systems versus standard practice, then
the energy savings achieved through these process system efficiency
measures can be used to document improved Percentage Improvement using
the Exceptional Calculation Methodology.  As Leonard mentioned, the
process energy will also impact cooling loads substantially, and
improvements to the cooling equipment and controls would also help the
overall building performance. 

Gail Stranske
CTG Energetics, Inc.

On 3/6/07, Leonard Sciarra <leonard_sciarra at gensler.com > wrote:

Maybe I am naive, and I have not read the NC 2.2 reference guide yet,
but process loads would affect an internally load dominated building,
ie, my cooling loads would be different hence my equipment selection
between a low density office vs a "financial trading floor" type
situation. LEED and gaming the system aside, from a real design point
they are important, and could affect envelope component selection.

 

Leonard Sciarra,  AIA, LEED ap
312.577.6580 (Dir)
G E N S L E R | Architecture & Design Worldwide
30 West Monroe Street
Chicago IL, 60603  
312.456.0123
leonard_sciarra at gensler.com      

 

 


  _____  


From: BLDG-SIM at gard.com [mailto:BLDG-SIM at gard.com] On Behalf Of Varkie
Thomas
Sent: Tuesday, March 06, 2007 11:23 AM
To: BLDG-SIM at gard.com
Cc: BLDG-SIM at gard.com
Subject: [BLDG-SIM] Process Loads and LEED

Vaibhav: Your reference makes the situation worse.    

The LEED energy savings rating system using the bottom line percent
savings over baseline appears to penalize buildings with high process
loads when you also consider LEED-NC Version 2.2 EA Credit 1 page 174
"The default process energy cost is 25% of the total energy cost for the
baseline building".  

What has the process energy cost (or the process energy use) got to do
with building design related to energy efficiency
(architecture-envelope, lighting, HVAC, DHW) except power supply for the
process?  The process energy within an office building can vary from 0.5
w/sf  (minimal use of computers and office equipment) to more than 6.0
w/sf for a financial/trading (Wall Street) type of building.  If the
baseline process energy is limited to 25% percent of total and the
proposed process energy use is more than 60% of the total then does this
mean that the building design is energy inefficient and does not qualify
for LEED certification?

Process energy could be part of the analysis if there is a baseline
standard for various types of computer and office equipment (varies
considerably and hard to define and prescribe for the numerous types
processes that occur in just office buildings) and the equivalent
proposed equipment is more efficient.  This comes under "Exceptional
Calculation Method" category along with several other energy efficient
building design options such as double-wall buildings for which you get
1 point (I think).

According to LEED-NC Version 2.2 EA Credit 1 page 174 "process energy is
considered to include, but is not limited to, office & general
miscellaneous equipment, computers, elevators & escalators, kitchen
cooking & refrigeration, laundry washing & drying, lighting exempt from
lighting power allowance (e.g. lighting integral to medical equipment)
and other (e.g. waterfall pumps).  Do all submissions for LEED
certification include all this.  At the construction documents
submission stage, what is the level of modeling detail that is required
regarding floor spaces and zones and all the systems, plant and
equipment shown on the drawings and specifications.  Can you use eQUEST,
select the type of building, and let the "Wizard" do the zoning and
assume most of the baseline data?   I don't think we are all playing the
same game, on the same level playing field and using the same rules to
show percent energy savings for LEED certification.

I also have some reservations about how various energy saving systems
are modeled with different computer programs.  The programs should be
studied and compared with the same case studies of different types of
buildings with different systems and plants and showing how each program
should be used to demonstrate energy savings from different energy
conservation measures such as UFAD.  

Building operation data can now be viewed on the web, collected for
meaurement & verification (M&V) and can be used to check computer
modeling results.  In the case of a M&V project at IIT, the web based
control systems show mainly temperatures.  Sub-meters and data loggers
should be included in the control specifications so that the performance
of the major systems, plant & equipment can be monitored separately and
compared with computer results.  At the moment we are comparing the
building utility meter reading with the bottom line building energy use
calculated by the computer program. 

Process loads do not affect energy code and Std-90 compliance since
"percentages" are not involved.  

V.C. Thomas


----- Original Message ----- 
From: Vaibhav Potnis <vaipotnis at hotmail.com> 
Date: Tuesday, March 6, 2007 8:14 am 
Subject: [BLDG-SIM] Process Loads and LEED 
To: BLDG-SIM at gard.com 

However I wanted to point out that for a LEED energy analysis, process
energy has to be maintained at 25% of total energy cost of the Baseline
Building Performance ( LEED- 2.2 Ref Guide page 182). I prefer taking
exceptional calculatins for process energy to simplify the calculations
as well as the review.

Hope this helps.

Vaibhav Potnis 
www.greenbuildingservices.com <http://www.greenbuildingservices.com/> 


  _____  


From: "Brandon Nichols" <BrandonN at Hargis.biz>
Reply-To: BrandonN at Hargis.biz
To: < BLDG-SIM at gard.com <mailto:BLDG-SIM at gard.com> >
Subject: [BLDG-SIM] Process Loads and LEED
Date: Mon, 5 Mar 2007 11:05:04 -0800

Varkie,

 

Something we have been noticing in schools lately is a high receptacle
load, which we believe is attributable to increased usage of computers,
approaching and in some areas exceeding 5 W per square foot -- the kinds
of loads I used to figure for "technology intensive" office areas just a
few years ago.

 

In researching an energy question for a school today, I came across this
web page and case study which I thought was relevant to your question:

 

http://www.energystar.gov/index.cfm?c=power_mgt.pr_power_management

 

 
<http://www.energystar.gov/ia/products/power_mgt/North_Thurston_Case_Stu
dy.pdf>
http://www.energystar.gov/ia/products/power_mgt/North_Thurston_Case_Stud
y.pdf

 

Essentially they summarize how, by consistently implementing power
management on computer monitors and CPUs using a simple utility program,
a cost savings of an estimated $15-$30 per computer per year can be
realized (on personal workstations I would add, not systems required to
be continuously online).  Multiplied across thousands of computers, the
bottom line annual savings can be substantial.

 

How to account for this in energy modeling software I have a general
idea:

 

1) Assign the baseline receptacle load to "occupied hours"; e.g. 5 W/SF
'always on'

2) Assign a diversified receptacle load schedule to the alternate
analyses

 

But quantifying the diversified load schedule is the hard part -- it
will no doubt vary significantly depending on the occupancy.  Though not
fully developed, this may provide a starting point for one method to
reduce process electrical loads in a LEED analysis.

 

 

Regards

 

Brandon Nichols, PE
Mechanical
HARGIS ENGINEERS
600 Stewart St
Suite 1000
Seattle, WA 98101
d | 206.436.0400 c | 206.228.8707
o | 206.448.3376 f | 206.448.4450
www.hargis.biz <http://www.hargis.biz/> 


  _____  


From: BLDG-SIM at gard.com [mailto:BLDG-SIM at gard.com] On Behalf Of Varkie
Thomas
Sent: Monday, March 05, 2007 7:14 AM
To: BLDG-SIM at gard.com
Subject: [BLDG-SIM] Process Loads and LEED

LEED-NC Version 2.2 page 173 "Optimize Energy Performance" states
"Demonstrate a percentage improvement in the proposed building
performance -- " and  "For the purpose of this analysis, process energy
is considered to include, but is not limited to, office and general
miscellaneous equipment, computers, elevators & escalators, kitchen
cooking & refrigeration, laundry washing & drying --- "

On page 174 "For EA Credit 1, process loads shall be identical for both
the baseline building performance and the proposed building performance"

Assuming the same space process load is used in the baseline and
proposed, then a building with a receptacle load density of say 1.0 w/sf
will produce a much greater percent savings compared to the same
building with a receptacle load density of say 6 w/sf.

Page 173 "must comply with the mandatory provisions (Sections --- ) in
Standard 90.1-2004 (without amendments)"  There is no mention of
Standards 62 for ventilation & occupancy density or Standard 55 for
indoor comfort conditions.  Does this mean that the baseline can be
based on the proposed ventilation, occupancy density and indoor comfort
conditions?  According to Standard 62-2004 the occupancy density for
general office space is 200 sf/P (from 142 sf/P in 62-2001 and I think
100 sf/P earlier).  This produces a low percent system outdoor air and
energy conservation measures such as "occupancy based ventilation" and
"outdoor air to relief air heat recovery" have little effect.  Std
62-2004 (also Std 90.1-2004 for lighting) provides design criteria for a
limited number of space types such as a prison cell (improved from 50
sf/P & 20 cfm/P in 62-2001 to 40 sf/P & 10 cfm/P in 62-2004) .  This
makes it difficult to determine baselin e conditions using Std 62.

I am looking at a financial institution building with high occupancy and
receptacle load densities.

 ----- Original Message ----- 
From: David S Eldridge <DSE at grummanbutkus.com> 
Date: Monday, March 5, 2007 10:36 am 
Subject: [BLDG-SIM] Process Loads and LEED 
To: BLDG-SIM at gard.com 

Varkie, I can see merits for the 2.1 method and the 2.2 method.  On the
one hand, the process loads are to some degree out of our control.  But
on the other hand, if you have a building with such massive load density
why would the rating system want to exclude all of that energy from
sustainable practices?

 

I like the idea of consistency when considering all of the energy for
energy optimization, on-site renewables and green power - there are
projects out there that might earn fewer EAC1 points under v2.2 than
under 2.1.  The percentage savings were changed between the versions so
it's hard to say if it is more or less likely to earn a certain amount
of EAC1 points - I would be interested to see a summary if the data is
available about EAC1 points under v2.1 compared to v2.2.  Probably about
the same?

 

For a high load density building like yours - definitely going to be
harder.  The only suggestion as far as EAC1 points that I could offer
would that if your design has receptacle load at 6 W/ft2 there is
probably a significant diversity in that load, maybe it won't turn out
as badly as you fear.

 

In regard to ventilation, you are going to use the outside air
requirements from the proposed design and apply that outside air
quantity to both models.  There isn't a "baseline ventilation rate" -
use equal CFM of OA for both models.  Also, OA may be determined from
local building codes rather than ASHRAE - that would also apply equally
to both models.

 

The one exception would be that Demand Control Ventilation could
potentially be used in the proposed model to reduce OA if DCV isn't
required prescriptively, and if your minimum OA from code is less than
what is required by ASHRAE 62.

Hope this helps!

 

David

 

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