[Bldg-sim] Low Ambient Strategy questioned in LEED Review

[Karen Walkerman]

Nick,

I mostly agree with your approach, however I disagree on one point - even
though desk lamps may be plugged-in and not permanently installed, if they
are part of the overall lighting plan, then I think that they should be
included in the proposed model and not in the baseline.  If you have low
footcandles in a space, but for whaterver reason, task lighting is not
required (this architectural studio uses giant multi-touch computers for
drawing), then task lights should be modeled equally in both models.

--
Karen



On Thu, Nov 17, 2011 at 4:36 AM, Carol Gardner <gems at spiritone.com> wrote:

>  tb,
>
> After, you have read through this  couple of times, or looked at it in an
> Excel table, you will figure out the changes you have to make and make
> them. Always remember, do the proposed case first and then back out the
> baseline, which must meet the applicable code.
>
> I think in a case like this building you would have had a different result
> if you had attached, or put into the form, what you were trying to do and
> how you did it. Your explanation is quite good and it gives the reviewers
> something to look at besides numbers. Then you get to exercise both sides
> of your brain.
>
> Cheers,
>
> Carol
>
>
>
> On 11/16/2011 10:26 PM, Tom Butler wrote:
>
>  Sorry for the long attachment here, but this LEED v2.2 EAc1 comment has
> me really confused so I want to post it in its entirety.
>
>
>
> 1.    The EAc1 Narrative describes the interior lighting design target
> for all studio spaces is 20 fc and that task lights have been modeled
> identically in the Baseline and Proposed case. However, according to the
> IESNA Lighting Handbook, ninth edition, the minimum horizontal design
> illuminance for art studios is 50 fc and for reading areas with handwritten
> tasks is 30 fc. The ASHRAE allowances represent the power allowance
> required to meet the minimum IESNA illuminance requirements for various
> space types. It is inappropriate to claim savings for designs that do not
> meet the minimum lighting level requirements and model the additional
> lighting power in the Baseline for lighting in the Proposed that is
> required to perform the anticipated tasks.
>
> Also, Table 1.4 reports that 4.02 kW of process lighting has been modeled
> in both cases, and it is assumed that this represents the task lighting.
> Process lighting is limited to the exempt interior lighting applications
> described in Section 9.2.2.3. Task lighting is regulated and thus not
> considered a process load. Section 9.6.3(b) does provide an additional
> allowance for task lighting when the Space by Space Method is used, but
> this may not be used for lighting required to raise the ambient lighting to
> meet the required lighting levels. If this additional allowance is used in
> the Proposed design, the Baseline must be modeled with the same power as
> the Proposed up to the 0.35 W/square foot allowance. Please remove all task
> lighting power from the Baseline model that is required to meet the IESNA
> recommended illuminance levels. If any of the additional allowance from
> Section 9.2.2.3 is applied to the Baseline case, provide calculations
> verifying that this additional lighting is not required in the Proposed
> case to meet the required illuminance levels and confirming that this only
> represents the portion of the additional allowance that is used in the
> Proposed case.
>
>  My first question; isn’t low ambient-task specific a commonly accepted
> energy use reduction strategy? Why would I model a lighting design in the
> proposed solution which isn’t installed and how would one determine,
> without an extensive lighting design effort, the appropriate lighting power
> to achieve 50fc, or 30fc? (not quite sure which one they want)
>
> Second, the spaces in question are architecture college studios. If the
> task lighting is a plug in desk lamp, provided by the student, then am I
> correct in assuming it’s not regulated by 9.2.2.3? I’ve assumed 60W per
> lamp as plug load, but there no way that the lamp type or light
> distribution can be controlled as defined in 9.6.3.b, nor is it a given
> that a lamp will be used.
>
>
>
> I’m at a loss as to how to respond to this.
>
>
>
> Thanks for any input.
>
>
>
> tb
>
>
>
> *Tom Butler*
>
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>
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