[BLDG-SIM] LEED points

Marcus Sheffer sheffer at paonline.com
Wed May 19 12:05:25 PDT 2004

Occupancy based controls require the modification of schedules and/or 
ventilation rates which is not allowed by the modeling protocols.

For LEED one can claim credit for these items by following Section 11.5 
Exceptional Calculation Methods in 90.1.  You have to do separate 
calculations and submit them for consideration by the review 
team.  Separate modeling runs can be an acceptable methodology as long as 
you explain the modeling procedure followed.  These are then subtracted 
from the original energy modeling like Renewable Energy.

Regarding daylighting modeling the review of LEED projects does not get to 
this level of depth.  We will not ask you the location of the sensor in the 
room.  We do use our experience to try and determine if the energy 
efficiency measures you have employed produce a reasonable savings.

For USGBC members you can join in some of the discussions of the EA TAG by 
signing up for the EA listserv.  Log in, visit your account and sign up for 
various committees.  Also check out the Credit Interpretation Requests 
(CIRs) where you can find many answers like the one regarding occupancy 
based controls I responded to above.

The EA TAG was also seeking new members very recently but I think the 
nominations/applications are closed.  The best way to have an effect on 
LEED is to get involved.

At 01:04 PM 05/19/2004, Varkie Thomas wrote:
>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 
>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 
>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
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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

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