[Equest-users] Building area method ASHRAE 90.1

Maria Karpman maria.karpman at karpmanconsulting.net
Tue May 22 15:28:54 PDT 2012


I agree with Patrick that building-wide LPD should never be used for the
proposed design. In the simulation, the lighting power density is always
coupled with a schedule, thus improving lighting that is on 24/7 should
result in higher kWh savings than equivalent improvement to lighting that is
on for just a few hours a day. Using uniform building-wide LPD in the
proposed design makes even less sense for projects that have daylighting. We
never use building area method for the baseline model either, which is an
easy way to avoid review comments like the one that Oscar got. Building area
method makes sense for prescriptive compliance with 90.1, but it is
surprising that it made its way into Appendix G.

 

Maria

 

From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Patrick J.
O'Leary, Jr.
Sent: Tuesday, May 22, 2012 5:49 PM
To: Sami, Vikram
Cc: eQuest Users; Oscar B.
Subject: Re: [Equest-users] Building area method ASHRAE 90.1

 

as long as a lighting system has been designed:

according to ashrae/appendix g the uniform/whole building method applies a
uniform lpd to the BASELINE building only while the PROPOSED uses what is
designed - so long as the design is based on the whole building area method.
the lpd of the PROPOSED design should not be applied uniformly to the
PROPOSED building simulation.  

see appendix g, table g3.1, section 6 lighting, subsection b, page 173
(2004), page 179 (2007).  user's manual pages g-17/18 (2004 & 2007)

i would suggest to quote table g3.1 when replying to the reviewer's comment.
i have had reviewer's tell me i have to use the space-by-space method in a
simulation for both proposed and baseline buildings.  this is not correct.
what is correct is that the simulation reflect the methodology used by the
lighting designer.  if the lighting design is based on the whole building
method then the whole building method maximum lpd is used in the BASELINE
building.  if the design is based on the space-by-space method then the
space-by-space maximum lpd for each space type is used in the BASELINE
building.  in either case the PROPOSED building should reflect what is
designed.  by 'what is designed' i mean look at the lighting plans, lighting
schedules, and enter the lpd for each space/zone (thermal block) based on
the number of fixtures, watts per fixture, and square feet of space.



On 5/22/12 2:15 PM, Sami, Vikram wrote: 

The building area method applies a uniform LPD to the entire building. If
you do that in your baseline, you need to apply a uniform LPD to you
proposed building too. 

In general, I don't recommend using the building are method - the space by
space method is a better approach. 

 

 

Vikram Sami, LEED AP BD+C

Sustainable Design Analyst

1315 Peachtree St. NE, Atlanta, GA 30309

t: 404-443-7462    f: 404.892.5823       e: vikram.sami at perkinswill.com
<http://www.perkinswill.com/> www.perkinswill.com

Perkins+Will.  Ideas + buildings that honor the broader goals of society

 

 

From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Oscar B.
Sent: Tuesday, May 22, 2012 4:38 PM
To: eQuest Users
Subject: [Equest-users] Building area method ASHRAE 90.1

 

 

 

How does the building area method work?

 

I just got a comment from the review team for a project pursuing LEED
certification.

 

I used the building area method for the baseline case and in the proposed
case I put the LPD from the lighting design. However they told me that the
same method has to be used in both cases.

 

Any help would be appreciate.






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