[BLDG-SIM] App G 2004 question

[Brandon Nichols]

All,
 
This is an old thread, but one I thought worth revisiting to see if
there have been any developments.  Specifically we are preparing a LEED
Silver project for submittal, and while we understand he intent of the
Appendix G 'multiple-orientation' and 'fenestration-leveling'
requirements, our evaluation is that they impose extensive calculation
requirements for arguably marginal returns on accuracy.
 
In the case of our specific building (as I would suspect the case of
90%+ of all buildings) there's simply no latitude to change the
orientation.  Similarly with glass distribution, the lobby and entryway
have the flexibility to be on one side and one side only of the
building, and thus distributing the glass equally amongst all facets for
the baseline model seems to add an unnecessary level of abstraction to
the comparative analyses.
 
Does imposing the requirement for analysts to spend considerable effort
developing fictitious baselines based on building orientations and glass
distributions that have 0% chance of construction seem to be a
reasonable requisite for LEED project certifications?  What I mean by
'considerable effort' is:
 
* That the all baseline numbers for each of the four orientations would
need to be extracted from the analysis software, averaged on a
spreadsheet, and a similar extraction done for all subsequent energy
efficiency measure (EEM) comparisons.  Posting these numbers from
analysis software to spreadsheets would be both time-consuming and
introduce another level of potential error, and thus require additional
error-checking.  
 
* That a new building would need to be developed, with glass
redistributed equally amongst all facets, for the four-point orientation
exercise described above.  Again, while this may sound reasonable from a
theoretical standpoint, practically speaking this requirement serves to
decouple the baseline from glazing-dependent energy efficiency measures.
How meaningful is changing the U-value or shading coefficient of the
glass in an EEM in comparison to a fictitious baseline, when the glass
distribution is crucial to determining whether or not the measure is
cost-effective?  As with building orientations, posting these numbers
from analysis software to spreadsheets would be both time-consuming and
additionally error-prone. 
 
All to fulfill the requirement of deriving a fictitious baseline for use
in the comparative analyses -- no doubt these requirements were
incorporated with good intention, but practical implementation
considerations seem to have not been considered carefully enough.
 
Further, we find the concept of comparing proposed energy efficiency
measures to a "code minimum" baseline building, oriented identically and
glazed similarly to each of the EEMs, to be intuitively more meaningful
to both the owner and project team (and thus presumably to the LEED
reviewer) than comparison to a fictitious baseline.  This approach
allows the baseline to reside in the analysis software, and EEM
comparisons accomplished using the built-in 'parametric run' features of
the analysis software (eQuest and others) to reduce the time-consuming
error-prone tediousness of extracting and posting numbers to a
spreadsheet for comparative evaluation.
 
Has anyone had success in obtaining LEED project approval when excepting
these 'building orientation averaging' and 'glazing-area leveling'
requirements?  What is required in terms of the LEED application to
waive these requirements?
 
Also, does anyone know if these requirements have been identified for
relaxation or revision in the next LEED update?
 
 
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

 
 
_________________________________________________

At 08:41 AM 1/24/2006, Bill Bahnfleth wrote:
 
Modeling the building in the specified orientations and averaging gives
an orientation-neutral baseline.

Appendix G has been developed with substantial input from experts at
PNNL and after discussions with USGBC. Glad to hear that modelers are
ignoring whatever they don't understand or find inconvenient.

Bill Bahnfleth
Member, ECB Subcommittee

At 09:42 PM 1/23/2006, Peter Alspach wrote:


	 A bit of a throw-back to the old 1989 version then?
	
	-----Original Message-----
	From: Kevin Warren [mailto:kevin at warren-energy.com]
	Sent: Monday, January 23, 2006 5:46 PM
	To: peter.alspach at arup.com; bldg-sim at gard.com
	Subject: RE: [bldg-sim] App G 2004 question
	
	Peter,
	
	I believe the intent is to give you a way to get some savings
from
	orienting your building with an eye toward savings. If you pay
attention
	to the sun in your design (passive solar and/or daylighting),
you should
	get some savings relative to the average of the rotated
orientations.
	Similarly, you could get a penalty if you have too much
west-facing
	glass.
	
	I'm not sure how strictly this provision is being enforced. Most
of the
	modelers I have spoken to ignore it, but that is a very
unscientific
	sample.
	These modelers may not be submitting to USGBC.
	
	For a utility incentive program, it often does not make sense to
do this
	rotation. Those incentive programs typically care about the
savings from
	incremental changes to the design, particularly those changes
that carry
	an incremental cost. I'm not sure how one would determine an
incremental
	cost for your building's orientation, so it is not a factor that
would
	typically be eligible.
	
	Kevin Warren, P.E., CEM, LEED AP
	Warren Energy Engineering, LLC
	(610) 255-3798 ph
	(610) 255-3406 f
	
	-----Original Message-----
	From: bldg-sim at gard.com [mailto:bldg-sim at gard.com]On
<mailto:bldg-sim at gard.com%5DOn>  Behalf Of Peter
	Alspach
	Sent: Monday, January 23, 2006 8:04 PM
	To: bldg-sim at gard.com
	Subject: [bldg-sim] App G 2004 question
	
	
	Anyone out there know the source of why one would be required to
	simulate a building in an orientation that it is not in? This
doesn't
	really make any sense to me - am I missing something?
	
	Peter
	
	-----Original Message-----
	From: bldg-sim at gard.com [mailto:bldg-sim at gard.com] On Behalf Of
Rohini
	Brahme
	Sent: Monday, January 23, 2006 1:13 PM
	To: bldg-sim at gard.com
	Subject: [bldg-sim] App G 2004 question
	
	I have a question about the Appendix G in 90.1, 2004.
	In Table G3.1 the baseline building is to be simulated as
follows:
	" Orientation. The baseline building performance shall be
generated by
	simulating the building with its actual orientation and again
after
	rotating the entire building 90, 180, 270 degrees, then
averaging the
	results. The building shall be modeled so that it does not shade
	itself."
	What does --- the building shall be modeled so that it does not
shade
	itself ---- mean?
	Does it mean that if there is, for example, an L shaped building
(which
	self shades), it has to be modeled as square? rectangle?
	Any thoughts on this appreciated.
	
	Thanks
	- Rohini
	
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_________________________________________________

William P. Bahnfleth, PhD, PE, Fellow ASHRAE

Professor of Architectural Engineering
Director, Indoor Environment Center

The Pennsylvania State University
104 Engineering Unit A
University Park, PA 16802 USA

voice: 814.863.2076 / fax: 814.863.4789
e-mail: wbahnfleth at psu.edu
www.arche.psu.edu/faculty/WBahnfleth/
http://www.engr.psu.edu/ae/iec/
_________________________________________________



 
Brandon Nichols, PE
Mechanical
HARGIS ENGINEERS

600 Stewart Street

Suite 1000

Seattle, WA 98101

www.hargis.biz

 

d | 206.436.0400  c | 206.228.8707

o | 206.448.3376  f  | 206.448.4450

 
 


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