[Bldg-sim] Window performance with frames

[Carol Gardner]

All,

Just a couple of comments. I became frustrated with the glass library data
years ago when I could never find a window that met the Oregon Code values
or the ASHRAE values. So I use Window vs x. It's quick and easy and you can
input data for all your sizes thus you have real output. Size makes a big
difference! I have neglected the frames up until lately because it's been
harder to get data related to them. When you get into it you find that
things like thermal breaks vary wildly in their structures. Who knew? I
thought a thermal break was a thermal break, but no, they can be made out of
various materials and sometimes don't really "break" the heat path at all.
Manufacturers like to use terms like "thermally improved". Just try to find
out what that means. Anyway, since so many windows are custom built in the
field it's good to get as much glass and frame info as possible so you can
accurately model them. Call it one of the final frontiers: a good thermal
break can really save energy. I always suggest it as an opportunity because
I know most developers will not consider them otherwise. They can cost a lot
although how much is debatable.

Last comment, and I apologize in advance Robin, Window is not paid for by
the Department of Energy; nothing is. It's paid for by us using our tax
dollars. At least they are going for something useful wrt Window.

Carol

On Thu, Jul 22, 2010 at 12:32 AM, mark dewsbury
<Mark.Dewsbury at utas.edu.au>wrote:

>  Dear Alex,
>
>
>
> I work in the HER validation field , so we need to know that we are
> modelling the right fabric matrix (framing factor and windows included). The
> software available in Australia only has the NFRC type table for selection,
> which is unsuitable for us. The get around the problem we can modify the
> data in the software’s scratch file. This is a file the software creates
> post data entry before simulation. We open this file and modify lots of
> parameters based on ‘as-built’ observations.
>
>
>
> Once you start playing at this level, you actually create as many windows
> as you wish. You just need & checking with the data entry. We mainly modify
> the framing ratios of a suitable NFRC window to match what is really in the
> wall. It is laborious, so I do believe that we need a parametric model
> within the HER software which can ultimately make the changes for us. The
> only other addition would then be a mullions tool to nominate how many
> vertical and horizontal mullions.
>
>
>
> We are to discuss this in Australia when I finish my current windowless
> project. But I have been advising another researcher with a windowed
> project.
>
>
>
> Mark Dewsbury
>
> Centre for Sustainable Architecture with Wood
> School of Architecture
> University of Tasmania
> Locked Bag 1324
> Launceston 7250
> ph: 03 6324 4089
> mob: 0417 290 807
> fax: 03 6324 4088
> e: mark.dewsbury at utas.edu.au
>   ------------------------------
>
> *From:* Alex Krickx [mailto:akrickx at seriousmaterials.com]
> *Sent:* Wednesday, 21 July 2010 3:22 AM
> *To:* mark dewsbury; bldg-sim at lists.onebuilding.org
>
> *Subject:* RE: [Bldg-sim] Window performance with frames
>
>
>
> Hi Mark,
>
>
>
> I agree with the point you make, but I want to expand the conversation a
> bit. Specifically, I aim to discuss the difference between how to use NFRC
> values and how to input values into energy modeling software.
>
>
>
> The NFRC value should be accurate for a window of the NFRC standard size.
> So a standard sized 1200mm x 1500mm fixed window will have a certain
> U-factor, SHGC and VT as part of its NFRC rating. But a different size will
> certainly have different performance values. I think NFRC is very useful in
> comparing Window A to Window B in a standard size, but you are right: once
> you’ve selected Window A we need to make sure that we have the right
> performance parameters for that sized window.
>
>
>
> I’ve been working on some projects that are aiming to be Passive House
> certified in which case they DO need to know how performance varies with
> size. We’ve worked out some formulas to calculate the full frame performance
> (only for U-factor at this point) on a range of our products. It’s tricky
> because you need to know the U-factor of each component (edge of glass
> against each part of the frame, each part of the frame, and COG) as well as
> the areas of each of those components which of course vary with different
> sized windows.
>
>
>
> I’m not sure what other manufacturers are doing to be able to provide this,
> but we have some of our product lines in a format that we can provide an
> NFRC-grade value for a non-NFRC sized window.
>
>
>
> If you want to see the calculations, you can follow this link:
> http://index.seriouswindows.com/passive-house.html and click “Download
> SeriousWindows for Passive House” at the bottom of the page or click here:
> http://index.seriouswindows.com/document-library/func-startdown/90/.
>
>
>
> The document describes how the window is broken into different sections and
> includes all the necessary info needed to calculate full frame performance.
>
>
>
> The last thing I’d like to add: It is probably simpler to upload WINDOW5
> data (I know eQUEST can import COG spectral data), specify your window size
> in the modeling software and specify your frame U-factor. Your software
> should take all that data and calculate what the full-frame data is pretty
> accurately.
>
>
>
> If anyone has any questions about this, feel free to contact me: generating
> these formulas took quite a bit of time and I’d be happy to share my
> learning.
>
>
>
> Regards,
>
> Alex Krickx
>
>
>
>
>
> Alex Krickx
>
> Building Energy Specialist
>
> [image: email_sig]
>
> 1250 Elko Dr, Sunnyvale, CA 94089
>
> (t) 408.541.8124
>
>
>
> *Warning:** The information contained in this e-mail may be privileged
> attorney-client communications or attorney work product and/or proprietary
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> recipient then you have received it in error and any review, distribution or
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>
>
>
>
>
>
>
> *From:* bldg-sim-bounces at lists.onebuilding.org [mailto:
> bldg-sim-bounces at lists.onebuilding.org] *On Behalf Of *mark dewsbury
> *Sent:* Monday, July 19, 2010 4:45 PM
> *To:* bldg-sim at lists.onebuilding.org
> *Subject:* Re: [Bldg-sim] Window performance with frames
>
>
>
> Dear All,
>
>
>
> Are we talking about the assessment for simple regulatory approval or are
> we talking about what a window really is. We have found dramatic variations
> between NFRC values and what actually goes into a building. I will not go
> into differences in measured infiltration rates as that is too random but
> the window framing factor is fairly parametric.
>
>
>
> The NFRC tables work on a sample window size (lest say 900mm x 1200mm).
> This is quite a small window when compared to most installations but;
>
> -          For windows smaller than the sample size the frame to galls
> factor is much higher,
>
> -          Conversely for large format windows commonly used in
> residential & commercial projects the framing factor is much less. In some
> test cases we have calculated framing factors changing from 18% to 8% or
> even less.
>
>
>
> Depending on Glass system and framing system this can create some
> interesting changes to thermal simulation results. One of my colleagues will
> hopefully publish something on this late 2010 or early 2011.
>
>
>
> Mark Dewsbury
>
> Centre for Sustainable Architecture with Wood
> School of Architecture
> University of Tasmania
> Locked Bag 1324
> Launceston 7250
> ph: 03 6324 4089
> mob: 0417 290 807
> fax: 03 6324 4088
> e: mark.dewsbury at utas.edu.au
>   ------------------------------
>
> *From:* Alex Krickx [mailto:akrickx at seriousmaterials.com]
> *Sent:* Saturday, 17 July 2010 5:05 AM
> *To:* Nick Caton; D. Charlie Curcija; Andy Hoover; Otto Schwieterman;
> bldg-sim at lists.onebuilding.org
> *Subject:* Re: [Bldg-sim] Window performance with frames
>
>
>
> Hi Nick,
>
>
>
> I think I know the answer to some of your questions, for some others I’m
> happy to share my thoughts, and for the remainder I have no clue.
>
>
>
> I have always assumed that for the DOE-2 Glass Library that those files
> have Window5 report files behind them – i.e. they’re not just single values
> for U, SHGC and VT. I could be mistaken though.
>
>
>
> Skipping number 2…
>
>
>
> I believe that Window5 is the same thing as WINDOW (technically, I think it
> is called WINDOW5 and there is/soon will be WINDOW6).
>
>
>
> Lastly – I’ve looked into some detail at how full frame U-factors are
> calculated and how they vary by size. So as a brief tangent, I thought I
> would look at whether SHGC varies by size too. I found that if a window had,
> say 0.5 SHGC COG and the window was 90% glass, 10% frame (by area) the
> resulting full frame SHGC was GREATER than (90%)*(0.5 SHGC). This means to
> me that the frame has some non-zero SHGC contribution. Granted, it was small
> (if I remember correctly on the order of 0.1) but still – non-zero!!! In my
> head I assumed that the frame would reflect additional heat through the
> window into the space – that may not be correct, but it made sense with my
> results.  I haven’t looked at VT that closely but I would assume the same is
> true – that the frame adds some small VT to the whole unit.
>
>
>
> Regards,
>
> Alex Krickx
>
>
>
>
>
> Alex Krickx
>
> Building Energy Specialist
>
> [image: email_sig]
>
> 1250 Elko Dr, Sunnyvale, CA 94089
>
> (t) 408.541.8124
>
>
>
> *Warning:** The information contained in this e-mail may be privileged
> attorney-client communications or attorney work product and/or proprietary
> and confidential.  If the reader of this message is not the intended
> recipient then you have received it in error and any review, distribution or
> copying of this message is prohibited and you are to notify us immediately
> by reply e-mail and delete the original message immediately.*
>
>
>
>
>
>
>
> *From:* Nick Caton [mailto:ncaton at smithboucher.com]
> *Sent:* Friday, July 16, 2010 10:27 AM
> *To:* D. Charlie Curcija; Andy Hoover; Alex Krickx; Otto Schwieterman;
> bldg-sim at lists.onebuilding.org
> *Subject:* RE: [Bldg-sim] Window performance with frames
>
>
>
> Mr. Curcija and everyone:
>
>
>
> If I may be so bold as to ask some “dumb” questions,
>
>
>
> -          I’m an individual who regularly relies on the DOE2 Glass
> library (a large excel file attached to any eQuest installation) to find
> window constructions whose NFRC framed U-value, visible transmittance, and
> SHGC/SC values best match those prescriptive values given for actual design
> models and for 90.1 baseline models.  Am I to understand all of my past
> models have a “10% to 100% error” with regard to the modeled behavior of the
> glazing?  Please explain!
>
> -          It sounds like the use of Window5 is pretty popular, and this
> ability to export a file which can be used by DOE2 has me intrigued – has
> NFRC or any other body decided to make representative report files to match
> 90.1’s baseline envelope requirements to encourage this procedure for
> comparative studies?
>
> -          Is Window5 the same thing as WINDOW?
>
> -          Furthering Otto’s original question, my reaction to a reviewer
> requiring “VLT including the frame” would be to first roll my eyes and then
> explain the frame has a VLT of zero, and is modeled distinctly from the
> glazing which has a VLT of ##%… am I misunderstanding the request there?
>
>
>
> Thanks!
>
>
>
> ~Nick
>
>
>
> [image: cid:489575314 at 22072009-0ABB]**
>
> * *
>
> *NICK CATON, E.I.T.***
>
> PROJECT ENGINEER
>
> 25501 west valley parkway
>
> olathe ks 66061
>
> direct 913 344.0036
>
> fax 913 345.0617
>
> *Check out our new web-site @ *www.smithboucher.com* *
>
>
>
> *From:* bldg-sim-bounces at lists.onebuilding.org [mailto:
> bldg-sim-bounces at lists.onebuilding.org] *On Behalf Of *D. Charlie Curcija
> *Sent:* Friday, July 16, 2010 9:16 AM
> *To:* 'Andy Hoover'; 'Alex Krickx'; 'Otto Schwieterman';
> bldg-sim at lists.onebuilding.org
> *Subject:* Re: [Bldg-sim] Window performance with frames
>
>
>
> Important thing to remember with windows is that the real number is the one
> that account for actual size and that takes into account angle dependent
> properties of glazing.  In most cases, single performance indices at
> standard conditions are used (i.e., U-factor, SHGC, and VT at normal
> incidence and standard environmental conditions) in an energy model of a
> building, which can produce errors anywhere from 10% to a 100%!!  The
> correct procedure is to either specify correct configuration and size of the
> product, with glazing specified  layer by layer (possible in EnergyPlus) or
> use what is called DOE2 or EnergyPlus reports from WINDOW program (DOE2
> report is used in DOE2 simulation program and E+ report is used in E+
> simulation program).  This is the only way to fully account for changes in
> size, angular properties of glazing and actual weather conditions.
>
>
>
> NFRC (National Fenestration Rating Council) has started to provide DOE2 and
> E+ report files in their new CMAST certification system, however number of
> products available is still relatively small and is limited to commercial
> projects.  EnergyPlus has also implemented in version 5.0 option to specify
> standard numbers at standard conditions (like the ones available from
> http://search.nfrc.org/search/searchDefault.aspx) and E+ uses then
> internal algorithms to provide glazing angular information and correction
> for actual conditions.  While it is best to model specific configurations
> for a window in THERM and WINDOW program (THERM is required to model frames
> and edge of glazing), this is not something that average user will be able
> to do, so getting whole product information from the NFRC web site and using
> E+ option to convert this data to something resembling real performance is
> still the best and easiest way to get actual information.  For commercial
> products http://cmast.nfrc.org provides full information that does not
> need any simplifications or corrections.
>
>
>
> Our energy simulation tools DesignBuilder and EFEN use EnergyPlus
> simulation engine, with the full range of options mentioned above and also
> provide hundreds of predefined fenestration products that can be matched to
> your actual product.
>
>
>
> D. Charlie Curcija
> *Design*Builder Software
> 16 Bridge St.
> Millers Falls, MA 01349
>
> Tel: (413) 256-4647
> Fax: (413) 256-4823
> cell: (413) 575-3487
> email: curcija at designbuildersoftware.com
> web: http://www.designbuildersoftware.com
> * *
>
> *From:* bldg-sim-bounces at lists.onebuilding.org [mailto:
> bldg-sim-bounces at lists.onebuilding.org] *On Behalf Of *Andy Hoover
> *Sent:* Friday, July 16, 2010 9:01 AM
> *To:* 'Alex Krickx'; 'Otto Schwieterman'; bldg-sim at lists.onebuilding.org
> *Subject:* Re: [Bldg-sim] Window performance with frames
>
>
>
> Hey all:
>
>
>
> We do not know Alex at all but completely support his position that it is
> the entire assembly/full frame in use that counts.   We are a building
> envelope consultancy and deal principally in the built market and see this
> issue all of the time where the performance of window, storefront and
> curtain wall units is dramatically different than that ‘calculated’ or
> provided.   As a matter of fact, it is the unfortunate norm.  At the end of
> the day it is about actual in use performance and that performance versus
> what was calculated.  I will stay away from installation difference in this
> one J.
>
>
>
> Anyway, we do agree with and have seen the truth to his assessment of frame
> differences.  It is only the performance of the entire assembly, at every
> level of a structure as a whole, that counts in the real world.
>
>
>
> Thanks and take care,
>
>
>
> Andy
>
>
>
> Andy Hoover
>
> Principal
>
> The BEST Consultant, Inc.
>
> Cell: 678-793-1159
>
> Office: 678-200-7648
>
> Fax: 678-827-0574
>
> Email: andyhoover at thebestconsultant.com
>
> Web: www.thebestconsultant.com
>
>
>
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> *From:* bldg-sim-bounces at lists.onebuilding.org [mailto:
> bldg-sim-bounces at lists.onebuilding.org] *On Behalf Of *Alex Krickx
> *Sent:* Wednesday, July 14, 2010 4:57 PM
> *To:* Otto Schwieterman; bldg-sim at lists.onebuilding.org
> *Subject:* Re: [Bldg-sim] Window performance with frames
>
>
>
> Hi Otto,
>
>
>
> Serious Materials provides full frame performance data here:
> http://index.seriouswindows.com/document-library/Datasheets/. I have also
> have some of our commercial packages modeled in curtainwall and storefront
> framing systems that I can provide upon request.
>
>
>
> Firstly let me say that Window5 is a great tool – I use it often and love
> it. The only thing I would advise is that there can be a wide distribution
> in frame U-factors. The default U-factor for a thermally broken aluminum
> (TBA) frame in Window 5 is U-1.0. Using THERM and Window5 I’ve seen TBA
> frame U-factors vary from as low as 0.8 to as high as 1.5. The resultant
> full-frame U-factor using these 2 differing TBA frames (and the same glass
> package) is: 0.29 (R-3.4) for the poorer performing frame, and 0.22 (R-4.5)
> for the better frame.
>
>
>
> I would say that putting either of those full frame u-factors in your
> energy model will yield pretty different results.
>
>
>
> I think it’s really important that we, as simulators and modelers, look at
> full-frame performance because this is the system that will be installed in
> the building. Center-of-Glass data can be useful comparing two different
> glass packages, but at the end of the day, it’s a framed system that will be
> installed and a framed system that should be analyzed. My 2¢.
>
>
>
> Regards,
>
> Alex Krickx
>
>
>
>
>
> Alex Krickx
>
> Building Energy Specialist
>
> [image: email_sig]
>
> 1250 Elko Dr, Sunnyvale, CA 94089
>
> (t) 408.541.8124
>
>
>
> *Warning:** The information contained in this e-mail may be privileged
> attorney-client communications or attorney work product and/or proprietary
> and confidential.  If the reader of this message is not the intended
> recipient then you have received it in error and any review, distribution or
> copying of this message is prohibited and you are to notify us immediately
> by reply e-mail and delete the original message immediately.*
>
>
>
>
>
>
>
> *From:* bldg-sim-bounces at lists.onebuilding.org [mailto:
> bldg-sim-bounces at lists.onebuilding.org] *On Behalf Of *Otto Schwieterman
> *Sent:* Wednesday, July 14, 2010 1:10 PM
> *To:* bldg-sim at lists.onebuilding.org
> *Subject:* [Bldg-sim] Window performance with frames
>
>
>
> Does anyone know of a window manufacturer web site that has literature on
> its windows including the frame? I am using Trace 700 for EA Credit 1 and
> the reviewer asked for manufacturer data sheets for window performance
> values (U-value, VLT and SHGC) including the frame.
>
>
>
> Your help is appreciated,
>
>
>
> Otto
>
>
>
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-- 
Carol Gardner PE
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