[Equest-users] URGENT: Window U-values: Total window assembly v/s Glass only
R B
slv3sat at gmail.com
Fri Jul 29 07:35:51 PDT 2011
If you look at the description for LV-D, it will tell you what all is
included in the U-value .It is either glass + internal film, or
glass+internal film+external film. What you enter in eQuest is either just
glass or glass + internal film (check the help on it to be sure). The values
you get from manufacturer are glass + internal film + outside film (someone
correct me if this is not the case).
So make sure that you are comparing the same combination of values.
-Rohini
On Fri, Jul 29, 2011 at 8:55 AM, Omar Katanani <omar at ecoconsulting.net>wrote:
> Thanks Bruce,
>
>
>
> I have an additional question:
>
>
>
> Ø In the “Glass prop.jpg” file attached, I entered the glass
> conductance as 0.6 Btu/h-ft2-F
>
> Ø In the “Window specs.jpg” file, I entered the frame width as zero.
>
> Ø However, when I look at my LV-D report, I notice that the Average
> U-value for the windows is 0.509 Btu/h-ft2-F
>
>
>
> Why is this number different from the glass conductance, given that I am
> assuming the frame width zero (i.e, the window is only composed of glass)?
>
>
>
> I need to figure this out in order to argue with the LEED Reviewer that
> eQUEST has the ability to capture frame effects.
>
>
>
> Many thanks,
>
> 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
>
>
>
>
> ------------------------------
>
> *From:* Bruce Easterbrook [mailto:bruce5 at bellnet.ca]
> *Sent:* 28 July 2011 19:36
> *To:* Omar Katanani
>
> *Subject:* Re: [Equest-users] URGENT: Window U-values: Total window
> assembly v/s Glass only
>
>
>
> I would try showing the frame effects are accounted for. I checked my
> ASHRAE Fundamentals text and the SHGC numbers seem close for 6mm glass
> double glazed with an aluminum frame in Table A8.2. This is a complicated
> area and I don't get this deep into it. This also seems to be a LEED US
> wrinkle from the question. The reference to referencing A8.2 would only
> apply to the base case anyway not to your proposed glass. So it would seem
> to me you show eQuest does account for the frames, which it does and that
> your proposed glass values are reasonable or you look at NFRC and pick a
> manufacturer making a window close to what you are proposing. I think the
> biggest problem is the reviewer is not very experienced and is just giving
> you a stock reply.
> Bruce
>
> On 28/07/2011 11:01 AM, Omar Katanani wrote:
>
> Hi Bruce,
>
>
>
> The project is in Lebanon, and there are pretty much no standards relating
> to energy whatsoever!
>
>
>
> The LEED Review I got is the following:
>
>
>
> *“It is It is unclear whether the window U-value of 0.26 and SHGC of 0.28
> used for the Proposed case accounts for the impact of the window frames on
> the whole assembly as required by ASHRAE modeling protocol. Please provide
> additional information to confirm that the framed assembly U-value was used
> for the Proposed case windows (e.g. showing that the whole window assembly
> has been tested by NFRC, or verifying that LBNL Window5 calculations have
> been provided for the whole assembly, or verifying that the frame effects
> are captured within the energy modeling software), or revise the model
> referencing ASHRAE 90.1-2007 Table A8.2 if needed.”*
>
>
>
> Can we argue that the frame effects are captured within eQUEST, as per the
> underlined phrase?
>
>
>
> Do you recommend using table A8.2, or are its U-values too high?
>
>
>
> 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
>
>
>
>
> ------------------------------
>
> *From:* Bruce Easterbrook [mailto:bruce5 at bellnet.ca <bruce5 at bellnet.ca>]
> *Sent:* 28 July 2011 17:36
> *To:* Omar Katanani
> *Cc:* Robby Oylear; Brad Robinson; equest-users at lists.onebuilding.org
> *Subject:* Re: [Equest-users] URGENT: Window U-values: Total window
> assembly v/s Glass only
>
>
>
> Hi Omar,
> This is where LEED and eQuest can get complicated. As you are outside
> the US the NFRC test results won't apply to you. This is a US window test
> standard. Being from Canada we have CSA test requirements for windows, we
> don't use NFRC. Basically you need to use the base standard for your
> country for your baseline. LEED Canada has adjusted the LEED documents in
> this area to reflect our testing agency and what we consider a base window.
> Has the country you are building in done the same?
> So to get you going I would assume a base window in eQuest for the
> baseline. Use 6mm clear glass, 1/2" air space, 6mm glass, metal spacer.
> Also pick a base frame as well, this would depend on the type of building
> you are doing, so select a plain frame in common use, if metal choose a
> frame without a thermal break. This should be easy to defend on a LEED
> review. If there is a specific country version of LEED for your location
> then you could adjust for this later once you get the required information.
> For your proposed you would build the window you are considering using the
> window manufacturers specs. All manufacturers will not offer all glass
> types. In the window industry there are the glass manufacturers, they make
> the glass. Window manufacturers buy the glass and make the frames. Now you
> can see the reasoning behind the NFRC testing and testing the total window,
> glass and frame, it is window manufacturer specific. But it does make a
> conflict with eQuest and the way it was programmed and the way windows are
> input. Realistically the frame it not going to make much difference except
> if it is metal and there is a thermal break. The glass being the
> overwhelming area of the window is going to have the largest impact. This
> is what you want to be playing with in eQuest, determining the cost
> effectiveness of different types of glass and the payouts. As long as you
> operate from a realistic baseline which is the current standard construction
> used in the country of the build then you can evaluate your proposed glass
> because you are looking at differential costs and savings. If your baseline
> changes it won't make very much difference, you have already been able to
> select your window, it will just effect the payback period and it will be a
> minor difference. This does let you get 98% of the window work done.
> Bruce Easterbrook P.Eng.
> Abode Engineering
>
> On 28/07/2011 08:40 AM, Omar Katanani wrote:
>
> 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?
>
>
>
> 1. 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?
>
>
>
> 1. 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
>
>
>
>
> ------------------------------
>
> *From:* Robby Oylear [mailto:robbyoylear at gmail.com <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® 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®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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