[Equest-users] URGENT: Window U-values: Total window assembly v/s Glass only

omar at ecoconsulting.net omar at ecoconsulting.net
Wed Jul 27 14:44:08 PDT 2011


Dear Robby,

Yes, I am modeling for LEED purposes.
I'll look into A8.2. But at least, is my method correct for the  
proposed scenario?

Brad: I think you need to enter the center of glass u-value in the  
"Glass Type", and then enter the frame properties in the "Window"  
properties...

Best,
Omar

Quoting Brad Robinson <brad.robinson at yahoo.com>:

>
>
> Is the u-value listed for a manufacturer and specific model on the  
> NRCAN website centre of glass or overall assembly?  Many windows are  
> custom made to suit so I am unclear if each individual custom window  
> would need to be tested.
>
>
>
> In eQuest, when entering the window, if the u-value represents the  
> whole window, including frame, do you need to enter a frame width,  
> conductance etc as well under the Window Frame section under Window  
> Properties?  Thanks.
>
>
> Brad Robinson
>
>
>
> ________________________________
> From: Robby Oylear <robbyoylear at gmail.com>
> To: Omar Katanani <omar at ecoconsulting.net>
> Cc: equest-users at lists.onebuilding.org
> Sent: Wednesday, July 27, 2011 12:32:08 PM
> Subject: Re: [Equest-users] URGENT: Window U-values: Total window  
> assembly v/s Glass only
>
>
> Omar,
>
> The answer depends on the purpose of your study.  If you're trying  
> to get results for a client on the impact of the glazing on their  
> energy performance, this may be adequate.  Make sure you've entered  
> in the framing information properly (metal vs. non-metal).
>
> I'd recommend opening up your simulation output results file  
> (xxxx.SIM) and going to the either the last page of the LV-D report  
> or sort through your LV-E report to see what value eQUEST has  
> calculated.  Compare these values to the ASHRAE Fundamentals results  
> for overall assembly values including frame to see how close you've  
> come.  I would not blindly trust that eQUEST will give you an  
> appropriate overall assembly value based on entering only the center  
> of glass number.
>
> However, if this is for a LEED study, this is not adequate.  This an  
> excerpt from an e-mail I sent out recently regarding LEED and NFRC  
> requirements.
>
> In order to meet LEED EAp2 Minimum Energy Performance, the project  
> must comply with all mandatory provisions of ASHRAE 90.1-2007.  
>  Section 5.4.2 Fenestration and Doors requires that fenestration  
> performance be determined per section 5.8.2.  Section 5.8.2.4  
> U-factor requires that the U-factor for the overall fenestration  
> area (including framing) be determined in accordance with NFRC 100.  
> If you do not have NFRC data available, values from section A8.2 are  
> the only acceptable alternative.
>
> Robby Oylear, LEED®AP BD+C
> Mechanical Project Engineer
> Energy Analyst
>  
> D206-788-4571 |C206-354-2721
> www.rushingco.com
>
>
>
>
>
> On Wed, Jul 27, 2011 at 8:14 AM, Omar Katanani  
> <omar at ecoconsulting.net> wrote:
>
> Dear all,
>>  
>> I have a small question regarding entering
> window properties to eQUEST:
>>  
>> I have read a lot of emails in the forum
> discussing NFRC testing, LBNL Window 5 import, and other topics that  
> I haven?t
> paid attention to before.
>>  
>> The way I modelled my windows is the
> following:
>>  
>> 	1. I have manufacturer?s specifications listing the glass  
>> U-values, not the total assembly.
>> 	2. In the ?Glass Types? (eQUEST Detailed Mode), I created glass  
>> types, and entered the glass conductance, visible transmittance,  
>> SC, and emissivity from the manufacturer?s details I have.
>> 	3. When creating windows, I specify which glass type (from the  
>> ones I created in step 2), in addition to the frame width and  
>> conductance.
>>  
>> I?m assuming that, given that I
> entered the u-values for the glass only, and then I entered information about
> the frame, then I need not worry about any conversions in U-values, since
> eQUEST has all the necessary information to calculate the equivalent  
> u-value of
> the whole pane + frame assembly, right?
>>  
>> I appreciate your feedback / comments
> today if possible, as this has become really urgent!
>>  
>> Many thanks,
>> Omar
>> ___________________________
>> Omar Katanani
>> Sustainable Design Engineer
>> Email: omar at ecoconsulting.net
>>  
>> EcoConsulting (Lebanon)
>> NahasBuilding, 4th floor
>> 4 St-Maron Street/ Georges Haddad Avenue
>> Postal Code: 2028 5806
> SAIFI
>> Beirut, Lebanon
>> Tel:          +961 (0) 1 971 266
>> Mobile:    +961 (0) 3 045 045
>>  
>> EcoConsulting (UK) Ltd
>> 28 Marshalsea Road
>> London, SE1 1HF
>> Tel:  +44 (0) 207 939 0989
>> Fax:  +44 (0) 207 939 0981
>> Website: www.ecoconsulting.net
>>  
>>  
>>  
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