[BLDG-SIM] Process Loads and LEED

Mike Tillou miket at etcgrp.com
Tue Mar 6 14:17:44 PST 2007


I went back and looked at the public review version of LEED 2.2 dated
December 2004 on the cover and October 19 in the footer.  Here is how
the original credit was proposed:
"Must be compared against a baseline building that both complies with
Appendix G to Standard 90.1-2004 (without amendments) and that has a
process energy consumption that is a minimum of 25% of the total energy
consumption for the baseline building."

In the final version of the the LEED 2.2 dated October 2005 that same
verbiage had been changed to 

"Must be compared against a baseline building that complies with
Appendix G to Standard 90.1-2004 (without amendments). The default
process energy cost is 25% of the total energy"

 I think the intent is that the default process energy cost used in the
calculation of LEED credits for V2.2 is a max of 25%.  If your building
has 60% process energy you would only have to count that portion of
process energy that equals 25% of the total energy.  This would level
the playing field for all buildings regardless of how much process
energy is used.  If a building uses less than 25% then you have to
justify the legitimacy of that claim.  

I think someone should submit a CIR asking whether this is the correct
interpretation of the Credit.

Respectfully,

Mike

Michael Tillou, PE 
ETC Group - Energy Engineering for a Sustainable Future 
Ph:413-458-9870 

	-----Original Message-----
	From: BLDG-SIM at gard.com [mailto:BLDG-SIM at gard.com] On Behalf Of
Varkie Thomas
	Sent: Tuesday, March 06, 2007 12:23 PM
	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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