[Bldg-sim] 90.1 Ap. G System selection: 5 stories + Underground - System 6 or 8?

Santiago Velez santiagogvelez at gmail.com
Thu Jul 2 20:05:50 PDT 2015


I agree with both of you. I guess my argument was that since these below
grade conditioned spaces would be served by separate HVAC system anyway,
then  they match the intention of the G.3.1.1.b. But I agree this is grey
area.
Good news is, this is early energy modelling to drive design, so it is
Baseline definition that will determine proposed HVAC system. First
proposal was an air cooled VRF system,  which in my experience against
baseline 8, will have difficulties (or be costly) achieving the substantial
targeted savings (34% again 90.1-2007 App. G). This would be more
achievable against a system 6.

Anyway, thanks for the insights!

Santiago.

On 2 July 2015 at 19:23, Nicholas Caton <ncaton at catonenergy.com> wrote:

> I would also go with 8, for simplicity.  You pretty clearly have 6 levels
> with conditioned spaces.
>
>
>
> Even if you do go through the effort to declare each underground level
> conditioned space as subject to G3.1.1 exceptions, that doesn’t reduce the
> quantity of floors with conditioned spaces for the whole project.
>
>
>
> That said, this is one of those situations where I’d subjectively agree
> it’s within the realm of reasonable interpretation to pursue the direction
> you’ve described with System type 6.  I might be more motivated to make
> that case if packaged DX systems per-floor are a closer approximation to
> the actual design equipment than a chiller plant.  I suspect it may
> ultimately be more effort than it’s worth however.
>
>
>
> ~Nick
>
>
>
> *NICK CATON, P.E.*
> *Owner*
>
>
>
> *Caton Energy Consulting*
>   1150 N. 192nd St., #4-202
>
>   Shoreline, WA 98133
>   office:  785.410.3317
>
> www.catonenergy.com
>
>
>
> *From:* Bldg-sim [mailto:bldg-sim-bounces at lists.onebuilding.org] *On
> Behalf Of *Javed Iqbal
> *Sent:* Thursday, July 02, 2015 2:55 PM
> *To:* Santiago Velez
> *Cc:* bldg-sim at lists.onebuilding.org
> *Subject:* Re: [Bldg-sim] 90.1 Ap. G System selection: 5 stories +
> Underground - System 6 or 8?
>
>
>
> In my opinion the *system type 8* would be applicable. As the *total
> conditioned area *is not explicitly mentioned so i presume it is more
> than 150,000 sqft (above grade floor+basement floor areas).
>
>
>
> Here are couple of reason which i could think of:
>
>
>
>
>
> i) per G3.1.1,  HVAC systems in the baseline building design shall be
> based on usage, number of floors, conditioned floor area, and heating
> source as specified in Table G3.1.1A and shall conform with the system
> descriptions in Table G3.1.1B.
>
>
>
> ii) per Table G3.1.1A, system 8 would be applicable if either of the
> condition is met number of floors OR conditioned area OR both
>
>
>
> iii) exception G3.1.1a would be applicable once you are decided with the *predominant
> system type* based on number of floors or conditioned area OR both per
> section G3.1.1. I strongly feel that exceptions are applicable only when
> the modeling scenario can not be addressed by the main sections which in
> your case is G3.1.1.
>
>
>
> Hope this helps!
>
>
>
>
>
>
>
> On Wed, Jul 1, 2015 at 7:54 PM, Santiago Velez <santiagogvelez at gmail.com>
> wrote:
>
> What is in your opinion the baseline for the following building:
>
> Floor area:12,000 sqm (130,000 sqft)
> Floors: 5 above grade, mostly conditioned. 5 underground parking, mostly
> unconditioned apart from some conditioned spaces in the first below grade
> floor.
>
> Predominant Use: Office (85% of sqft),
> Secondary use: bank in PB and below grade; Kitchen, below grade; control
> security room, below grade.
>
> I'm in between baseline 6 or 8. If conditioned spaces below grade fall
> under exceptions to G3.1.1 b. then can I consider for the baseline that the
> predominant building has 5 floors instead of 6?
>
> Thanks in advance.
>
> Santiago.
>
>
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>
> --
>
>
>
> Javed Iqbal, LEED AP, CEA
> Sr. Energy Analyst
>
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