[BLDG-SIM] Process Loads and LEED

[Brandon Nichols]

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


  _____  

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.

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