[Equest-users] URGENT: Window U-values: Total window assembly v/s Glass only
Omar Katanani
omar at ecoconsulting.net
Thu Jul 28 05:40:25 PDT 2011
Dear all,
Thank you for your responses.
1. Are the NFRC testing and the values in table A8.2 used for the
Baseline, Proposed, or both scenarios?
2. Let's say I do not have NFRC test results and decide to use the
values in table A8.2. For a clear double glazed and metal frame type, I
get an assembly U-factor of 5.1. How can I input this into eQUEST? As
far as I know, I can enter the glass properties and the frame
properties. Do I have to play with the glass properties and check the
LV-D report for the calculated Assembly u-value?
Similarly, for the baseline, Tables 5.5-1 to 5.5-8 of ASHRAE 90.1
provide the assembly u-values for vertical glazing. How can I enter
these values into eQUEST?
3. I am attaching the specs of the proposed glazing. These numbers
are for the glass only (note that the u-values reported are NFRC ones).
Additionally, I know that the frame will be aluminium. Do I still need
NFRC U-values for the whole assembly, or is the NFRC usually for the
glass only? If yes, how can I calculate the whole assembly U-value
(given that eQUEST doesn't have the ability to calculate this)
Thanks for clarifying this, as my project is outside the US and we are
not too familiar with standards such as NFRC.
Best regards,
Omar
___________________________
Omar Katanani
Sustainable Design Engineer
Email: omar at ecoconsulting.net
EcoConsulting (Lebanon)
Nahas Building, 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 <http://www.ecoconsulting.net/>
________________________________
From: Robby Oylear [mailto:robbyoylear at gmail.com]
Sent: 28 July 2011 00:53
To: Omar Katanani
Cc: Brad Robinson; equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] URGENT: Window U-values: Total window
assembly v/s Glass only
Omar,
To directly answer your question:
"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?"
No. Your method will result in an assembly U-value based on your input
glass conductance and whatever default frame properties that the eQUEST
wizard will use. I have never tried to let eQUEST determine an assembly
value, as NFRC values are required for LEED and code compliance studies.
I would not be surprised if the values eQUEST is calculating (shown in
LV-D and LV-E reports like previously mentioned) are much different than
what you'll actually see in the test results.
Again, NFRC values are a LEED requirement, so unless you're just doing
preliminary analysis for a client, you need to receive NFRC simulation
reports or certified product directory numbers in accordance with NFRC
100.
Robby Oylear, LEED(r) AP BD+C
Mechanical Project Engineer
Energy Analyst
D 206-788-4571 | C 206-354-2721
www.rushingco.com <http://www.rushingco.com/>
On Wed, Jul 27, 2011 at 2:44 PM, <omar at ecoconsulting.net> wrote:
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(r)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
<tel:%2B961%20%280%29%201%20971%20266>
Mobile: +961 (0) 3 045 045
<tel:%2B961%20%280%29%203%20045%20045>
EcoConsulting (UK) Ltd
28 Marshalsea Road
London, SE1 1HF
Tel: +44 (0) 207 939 0989
<tel:%2B44%20%280%29%20207%20939%200989>
Fax: +44 (0) 207 939 0981
<tel:%2B44%20%280%29%20207%20939%200981>
Website: www.ecoconsulting.net
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