[Bldg-sim] Baseline and Proposed HVAC system

[amit bhansali]

Hi Rohini,
i was addressing whats written in ASHRAE 90.1-2007 in section 9.4 for the
mandatory lighting standards. As i went through and had some inputs, what
appendix G really means is that we do not model the automatic lighting in
the baseline that makes the model with the maximum allowed LPD with a
schedule. However, in the proposed case the schedule remains the same but a
10% reduction on LPD could be done to account for the automatic lighting.

Now, my confusion is what Jorge said: "Your baseline for the renovation
portion of the work is in essence the existing conditions (envelope
components, equipment, layout, efficiencies, LPD, etc.)"
If that sentence were to be true than should i model the building with all
the pre-renovation values for envelope, LPD and consider that as the
baseline. Again, i have said this earlier that this is a major renovation,
and in the GBCI review, it has been clearly mentioned and i would
quote " Renovation
projects need to model the baseline case mechanical system following the
table G3.1.1A mapping as new construction projects" . The only point where
the existing values would hold good in a simulation would be on the envelope
side since in Appendix G #5 for Building Envelope, the (f) point
states that"for existing
building envelopes, the baseline should reflect existing conditions prior to
any revisions that are part of the scope of work being evaluated"

Please send me your suggestions and comments.

On 29 September 2010 11:24, R B <slv3sat at gmail.com> wrote:

> Amit,
> On your second question - as far as I remember (this is 2004 standard), the
> mandatory occupancy sensors are on a space basis. So if you have occupancy
> sensors in more spaces than what is mandatory, you can have the savings due
> to them in these extra spaces. If the baseline does not have LED lighting,
> then the proposed will have lower lighting wattage than baseline, giving you
> lighting savings.
> -Rohini
>
> Rohini Brahme, Ph.D., LEED AP
> Building energy analysis, tool development, and training
> Dallas/Fort Worth, TX
>
>   On Wed, Sep 29, 2010 at 10:58 AM, amit bhansali <amitbhansali7 at gmail.com
> > wrote:
>
>>   Hello all,
>> There are two things that are confusing me right now:
>> 1. I am trying to understand a comment that we recieved from GBCI
>> regarding the HVAC system that we used to model one of our projects. It is a
>> existing building with AHU's, Chillers, Electric Heat and FPB's with a
>> square footage of about 90000sf. I understand that the according to table
>> G3.1.1B , the HVAC system should be Type 6 and should have a direct
>> expansion type cooling and not a chiller for the baseline building. However,
>> since the existing building already has a chilled and the proposed would
>> have a new more efficient chiller, shouldnt i model the baseline with a
>> chiller as well since the existing building already has a chiller. Does
>> anyone have experience with this?
>> The renovation in the building is a major one.
>>
>> 2. Since the building is more than 5000sq ft , it has a mandatory
>> requirement of having occupancy sensors/motion sensors installed in the
>> baseline case. Now again, the existing building didnt have any motion or
>> occupancy sensors and did not have the LED lighting as in proposed building.
>> But since having the sensors is mandatory , do i not get any categpry for
>> having occupancy sensors? Also, if the occupancy sensors are to be modeled
>> should the percentage reduction in LPD to account for it in the simulation
>> from Table G3.2 be taken into consideration in Baseline as well as proposed
>> which would essentially mean that i would have no energy savings for
>> lighting?!!
>>
>> Your help is highly appreciated.
>>
>> --
>> Thanks
>>
>> Sincerely,
>> Amit Bhansali, M.S. , EIT
>> Command Commissioning, LLC
>> 8410, Sterling St
>> Irving, TX  75063
>>
>> Office :(972)-929-1199 (Ext:328)
>>  Mobile: (+1)972-207-5180
>>              (+1)405-312-1047
>>
>> www.command-cx.com
>> www.godparents.in
>> Please do not print this e-mail unless necessary
>>
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>


-- 
Thanks

Sincerely,
Amit Bhansali, M.S. , EIT
Command Commissioning, LLC
8410, Sterling St
Irving, TX  75063

Office :(972)-929-1199 (Ext:328)
 Mobile: (+1)972-207-5180
             (+1)405-312-1047

www.command-cx.com
www.godparents.in
Please do not print this e-mail unless necessary
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