[BLDG-SIM] LEED points

[Varkie Thomas]

The EA-TAG should also consider that the infiltration due to stack
effect in a high-rise building is affected by having entrances with a
vestibule and revolving doors.  

 

Can occupancy based lighting and occupancy based ventilation be
considered for LEED credits under "Optimize Energy Performance"?   How
should these options be modeled?  In DOE2 the design ventilation value
can be varied by using the occupancy schedule for the minimum OA
schedule.  Occupancy based lighting would have to be "on-off" depending
on occupancy = 0 or occupancy > 0.   This can vary with the space type
and it is difficult to determine for buildings zoned as perimeter and
interior only.  Can we assume say an average 5% off the lighting
schedule for installing occupancy based lighting controls?  How would
you model daylighting controls for LEED credits?  In DOE2 you can locate
the light sensor close to the window and assume it represents a
perimeter space with any depth.  Are there limits on lighting sensor
location and perimeter space depths, areas and volumes?  The ASHRAE
STD90 prescriptive standards are stringent in all categories of
envelope, lighting and mechanical systems.  From the responses I have
received so far, significant energy cost savings (such as 60%) can be
achieved with daylighting controls (not accepted by most energy codes),
renewable energy sources such as PV and GSHP, and thermal storage in
situations where there is a big difference between peak and off-peak
electric rates.  

 

I think that different types of standard building models should be
defined with case studies.  It is difficult to figure out the intent of
STD90 and to convert STD90 legal descriptive language into a base
prototype building model.  10CFR435 is more precise.  I think that the
"Energy & Atmosphere" section of LEED should be explained in more detail
and with examples.

 

Varkie Thomas

Skidmore, Owings & Merrill LLP

 

-----Original Message-----
From: postman at gard.com [mailto:postman at gard.com] On Behalf Of Marcus
Sheffer
Sent: Wednesday, May 19, 2004 11:00 AM
To: BLDG-SIM at gard.com
Subject: [BLDG-SIM] Infiltration: Standard versus Proposed Design

 

Right now infiltration reduction is not an eligible item for energy cost
reduction for LEED.  Infiltration rates must be the same in the proposed
and budget buildings.

My understanding is that the Energy & Atmosphere Technical Advisory
Group (EA TAG) of the USGBC is considering this issue with an eye toward
developing a modeling protocol.

I am aware of at least two projects that have applied for savings in
this area which have been put on hold (the LEED points were denied
pending further input from the EA TAG).  


As At 10:33 AM 05/19/2004, you wrote:



Can infiltration be considered in comparing standard versus proposed
design models using the ECB method and for LEED credits under "Optimize
Energy Performance"?  Typically we use the same criteria in both models,
but this is a particular case of a proposed double-wall building.
"10CFR435 Table 402.2.1. - Air Leakage for Fenestration & Doors Maximum
Allowable Infiltration Rate" provides standard model information for
federal buildings.  For example, the infiltration rate is 0.15 cfm/ft2
for fixed aluminum windows.  Can this be used for LEED standard design
and can a lower rate be used for double wall buildings?
 
The CFR table does not account for Heating & Cooling Degree Days as with
Table-B Building Envelope Requirements of STD90.  In my opinion, the
peak design infiltration rate should be varied from maximum in winter to
minimum in summer (typically zero for pressurized buildings) using a
schedule.  The maximum, of say 0.15 cfm/ft2, would apply to a cold
climate such as Chicago and it should be scaled down for warmer
climates.  Since DOE2 does not allow infiltration rates on the basis of
cfm/ft2 of wall or window area or cfm per lineal foot of window
perimeter, we create a typical perimeter space and convert the window
based infiltration rate to cfm/ft2 of space area or space air changes.
We then look at the results in "REPORT- LS-C BUILDING PEAK LOAD
COMPONENTS" of the DOE2 output to see if the infiltration load looks
reasonable (relative to the other loads) for the location and type of
building and make adjustments by trial and error.  Judgment and
experience is considered more reliable than theoretical mathematical
models.  The BEPS and BEPU reports in DOE2 should separate out the
infiltration loads from the heating & cooling loads.  Any comments?
 
Thanks for the comments and suggestions to using different utilities in
standard versus proposed design.  They were very helpful in making some
decisions here.  Most of the responses seem to go directly to the person
asking the question.
 
Varkie Thomas
Skidmore, Owings & Merrill LLP
 
 
 

 
 
 
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Marcus B. Sheffer                          energy & environmental
consulting
Energy Opportunities, Inc              717-292-2636
1200 E Camping Area Road            Fax: 717-292-0585     
Wellsville, PA USA 17365-9783        sheffer at sevengroup.com
a 7group company                        www.sevengroup.com
<http://www.sevengroup.com/> 

 
 
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