[BLDG-SIM] Process Loads and LEED

Leonard Sciarra leonard_sciarra at gensler.com
Tue Mar 6 09:52:03 PST 2007


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