[BLDG-SIM] Process Loads and LEED

[Brian Thornton]

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_Study.p
df>
http://www.energystar.gov/ia/products/power_mgt/North_Thurston_Case_Study.pd
f

 

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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