[Equest-users] wwr calculation

deepika khowal deepika.khowal at gmail.com
Thu Oct 20 10:56:45 PDT 2011


I never mentioned am using 90.1 standard.
it was a generic question about calculating wwr .
and if you say its not important to model unconditioned spaces, how do you
account for heat transfer between conditioned and unconditioned spaces?

Thanks
Deepika

On Thu, Oct 20, 2011 at 3:33 AM, Pasha Korber-Gonzalez <
pasha.pkconsulting at gmail.com> wrote:

> I disagree with both of you.
>
> First of all, who models Garages in their models anyway?  What a waste of
> time.---this scews the gross floor area, and nothing in a parking garage
> impacts the HVAC equipment loads of the conditioned spaces....you can always
> input your garage vent fans and lighting as single exterior load input
> numbers in your model which simplifies the whole modeling project and
> billable time spent WITHOUT compromising on the calculations of energy
> use....
>
> Second of all---poor example for offering windows in a parking garage--this
> is never real life, and a non-applicable example doesn't "hold water".   At
> least give an example that is comparable to real life situations...  Parking
> garages are either open air, or underground (without fenestration...)   Have
> you ever had a project where Mechanical cooling needed to be provided to a
> parking garage?  I hope not because these are considered transient space
> types.
>
> If you are modeling your LEED buildings according to appendix G --90.1 you
> do not include the above grade garage wall area in your gross building WWR
> calculation.
>
> FOURTH---Deepika---you are modeling a residential home from your picture
> you sent us.   YOU CANNOT USE ASHRAE STANDARD 90.1 TO MODEL LOW-RISE
> RESIDENTIAL BUILDINGS!
>
> You are using and interpreting the wrong standard, you need to use ASHRAE
> Standard 90.2 for Non-commerical Residential buildings.    You will need to
> use this new reference as everything you are referring to does not apply for
> your project or your project model.
>
> The real answer to your question is the Nebraska Cornhusker football team
> IS BETTER than the Virgina Tech Hoakies!     GO BIG RED!!!!
> Pasha
>
>
> On Wed, Oct 19, 2011 at 3:15 PM, deepika khowal <deepika.khowal at gmail.com>wrote:
>
>> I agree with James .
>> if its unconditioned space, we should not claim the window area . that way
>> we can have higher WWR for rest of conditioned spaces.
>>
>>
>> On Wed, Oct 19, 2011 at 1:56 PM, James Hansen <JHANSEN at ghtltd.com> wrote:
>>
>>> I don't think I agree with this advice****
>>>
>>> ** **
>>>
>>> Under ASHRAE 90.1-2007, Section 5.2.1, part of the requirements for the
>>> PRESCRIPTIVE method requires that "the vertical fenestration area does not
>>> exceed 40% of the gross wall area for each *space-conditioning category*".
>>> ****
>>>
>>> ** **
>>>
>>> The definition for "space conditioning category" simply says:****
>>>
>>> ** **
>>>
>>>                 non-residential conditioned space,****
>>>
>>>                 residential conditioned space, and****
>>>
>>>                 nonresidential and residential semiheated space****
>>>
>>> ** **
>>>
>>> It doesn't list unconditioned space.  Now I know this info is listed in
>>> the prescriptive requirements, but if it was my model, and I had a garage
>>> that had 100% window area, there is no way I would count that towards the
>>> gross WWR, particularly if I was applying for LEED, and these
>>> inconsequential windows pushed my WWR above 40% and thus penalized my
>>> proposed building.  In fact, I might not even model the windows, unless I
>>> felt they were going to superheat the garage and start impacting adjacent
>>> space cooling loads.****
>>>
>>> ** **
>>>
>>> Just my opinion...****
>>>
>>> ** **
>>>
>>> *GHT Limited
>>> **James Hansen, P.E., LEED AP*
>>> Senior Associate
>>> 1010 N. Glebe Road, Suite 200
>>> Arlington, VA  22201-4749
>>> 703-243-1200 (office)****
>>>
>>> 703-338-5754 (cell)
>>> 703-276-1376 (fax)****
>>>
>>> www.ghtltd.com****
>>>
>>> ** **
>>>
>>> *From:* equest-users-bounces at lists.onebuilding.org [mailto:
>>> equest-users-bounces at lists.onebuilding.org] *On Behalf Of *PKConsulting
>>> *Sent:* Wednesday, October 19, 2011 4:04 PM
>>> *To:* deepika khowal
>>> *Cc:* equest-users at lists.onebuilding.org
>>> *Subject:* Re: [Equest-users] wwr calculation****
>>>
>>> ** **
>>>
>>> It doesn't change for unconditioned or conditioned.  It is only a
>>> function of gross wall area (ft2) and window area (ft2).   Don't think too
>>> hard about this.  You are looking for a needle in the wrong haystack.   This
>>> one is straight forward with no tricks...****
>>>
>>> ** **
>>>
>>> WWR is for whole bldg not space by space.****
>>>
>>>
>>> Pashalu****
>>>
>>>
>>> On Oct 19, 2011, at 12:20 PM, deepika khowal <deepika.khowal at gmail.com>
>>> wrote:****
>>>
>>> Thanks Pasha****
>>>
>>> ** **
>>>
>>> yes , i have been using LV-d report.****
>>>
>>> ** **
>>>
>>> Am confused how it work for an unconditioned space.****
>>>
>>> Thanks****
>>>
>>> On Wed, Oct 19, 2011 at 11:01 AM, PKConsulting <
>>> pasha.pkconsulting at gmail.com> wrote:****
>>>
>>> It should be the gross wall area for everything above ground.  Use the
>>> lv-d report to find the numbers to calculate the overall WWR for your entire
>>> bldg.   There is a summary page at the end of the lv-d report.  Look for the
>>> line called-'all walls'.  You can use those numbers to calc WWR percentage.
>>>
>>> Pashalu****
>>>
>>>
>>> On Oct 19, 2011, at 11:39 AM, deepika khowal <deepika.khowal at gmail.com>
>>> wrote:
>>>
>>> > Hi all
>>> >
>>> > I have a question about calculating WWR.
>>> > for example, if the south wall area is 700sf and total window area is
>>> 70sf then the WWR should be 10%.
>>> > but if 50% of south wall is part of a garage and is unconditioned, then
>>> in calculating WWR , should I include only the wall area for conditioned
>>> space or it should include complete facade?
>>> > Thanks
>>> >
>>> > Deepika
>>> >
>>> >
>>> >
>>> >****
>>>
>>> > <image.png>
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>>> ** **
>>>
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>>
>>
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