[Equest-users] Window replacement and infiltration rate changing

Chris Jones cj at enersave.ca
Wed Sep 15 16:07:10 PDT 2010
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ASHRAE 90.1-1989 prescribed the amount of 
infiltration to use in the design and budget 
cases as 0.038 cfm/sq. ft. of gross exterior wall 
area.  I believe that subsequent versions of 90.1 
dropped any reference to modelling infiltration 
rates.  The infiltration is "on" when the fans are off.

The MNECB/CBIP in Canada uses 0.05 cfm/sq. ft of 
gross exterior wall area - with a schedule on all of the time.

Who knows where those numbers came from and it 
doesn't really answer the question of how much 
infiltration will be saved with new windows but it gives a starting point.



At 06:16 PM 15/09/2010, Alex Krickx wrote:
>Content-Language: en-US
>Content-Type: multipart/related;
> 
>boundary="_005_B8B836A09111F041A16C8A3690FB3563AFF4FE9861EXVMBX0156exc_";
>         type="multipart/alternative"
>
>Yeah, it does sound high, doesn’t it? But when 
>compared to the maximum level for new windows of 
>0.3, then it doesn’t sound as high
 new windows 
>must be 3x less leaky than old ones – that 
>sounds like the right reduction to me.
>
>The only link I could find on performance of old 
>windows was this one: 
><http://www.bfrl.nist.gov/IAQanalysis/CONTAM/table00_arld.htm>http://www.bfrl.nist.gov/IAQanalysis/CONTAM/table00_arld.htm 
>
>
>It gives leakage areas in “area per linear meter 
>of seam”. A colleague converted this to leakage 
>area in CFM/SF at 75 pa. His number was 1.4 
>CFM/SF based on the table (not sure which value he used).
>
>As a thought: perhaps 1 CFM/SF seems too high 
>because we imagine it as the infiltration for a 
>whole wall, when in actuality it only applies to 
>the window? Assuming the wall has little 
>infiltration, a 25% WWR would bring 1 CFM/SF 
>(window) to around 0.25 CFM/SF (whole façade) – 
>probably a little higher if accounting for the 
>wall leakage, but not significantly so. Does 
>that number still raise alarm bells? Not to me, 
>but I don’t have as good a feel for this as Carol does.
>
>I’ve definitely seen some leaky windows – 
>unfortunately I’ve never tested how leaky they 
>are so I’m stuck with looking for industry 
>papers and best practice.  I definitely would 
>like to learn more about this though. Typical 
>infiltration values of old windows seems to be a 
>big question mark with people I’ve asked
.
>
>Regards,
>Alex
>
>
>From: Carol Gardner [mailto:cmg750 at gmail.com]
>Sent: Wednesday, September 15, 2010 2:57 PM
>To: Alex Krickx
>Cc: YingQi Chen; equest-users at lists.onebuilding.org
>Subject: Re: [Equest-users] Window replacement and infiltration rate changing
>
>Wow! It seems like 1 cfm/sf for infiltration 
>would be a lot. The people's hair next to the 
>windows would be blowing all around! That's the 
>average number I use for HVAC ventilation.
>
>Carol
>On Wed, Sep 15, 2010 at 2:36 PM, Alex Krickx 
><<mailto:akrickx at seriousmaterials.com>akrickx at seriousmaterials.com> wrote:
>Hi Yingqi,
>
>I’m pretty sure eQUEST does not automatically adjust infiltration rates.
>
>If you search through the archives and look up 
>“infiltration windows” you can find some 
>relevant posts. I’ve attached one email that was 
>sent around earlier this year describing one way 
>to change the infiltration between current and proposed cases.
>
>I don’t think you can apply a percentage 
>reduction without some more information. I 
>believe that the requirement to meet the DOE’s 
>VPP for windows is a maximum infiltration of 0.3 
>CFM/SF – this leads me to believe that some new 
>windows have more infiltration than this. My 
>company manufacturers windows with infiltrations 
>as low as 0.01 CFM/SF. I’m having a hard time 
>finding a source, but I’m pretty sure I’ve heard 
>of modeling existing windows with infiltration 
>as high as 1 CFM/SF. A building with a large WWR 
>and very leaky windows could substantially 
>reduce whole-building infiltration values.
>
>Good luck!
>Alex Krickx
>
>
>Alex Krickx
>Building Energy Specialist
>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: 
><mailto:equest-users-bounces at lists.onebuilding.org>equest-users-bounces at lists.onebuilding.org 
>[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Carol Gardner
>Sent: Wednesday, September 15, 2010 2:19 PM
>To: YingQi Chen
>Cc: 
><mailto:equest-users at lists.onebuilding.org>equest-users at lists.onebuilding.org
>Subject: Re: [Equest-users] Window replacement and infiltration rate changing
>
>If eQUEST changed the infiltration between the 
>two cases you would be able to see the change in 
>your .inp deck. I'm not sure what the impact of 
>doing the change using the EEM Wizard vs. simply 
>copying and renaming your input deck and making 
>the change in it's own .inp deck would be. You 
>could experiment and see if there's a 
>difference. If it doesn't change your 
>infiltration I would lower the perimeter 
>infiltration rate conservatively by a fixed 
>percent. You might Google infiltration rates on 
>line and find some information related to how 
>much to expect for a single pane window to a 
>double pane window. Also, be sure to account for 
>your frames, too. Are they thermally broken? 
>Does the frame material change, etc.
>
>Carol
>On Wed, Sep 15, 2010 at 2:05 PM, YingQi Chen 
><<mailto:yingqi.chen at pertan.com>yingqi.chen at pertan.com> wrote:
>Dear eQuester:
>
>I want to run a simulation by EEM wizard. I want 
>to replace exiting single pane, clear windows 
>with double pane clear windows for a school building.
>
>I changed the class type form single pane clear 
>to double pane clear windows.  The energy saving 
>doesn’t look good.  I have two following questions need someone's guidance.
>
>Question 1:
>
>My question is that this EEM will reduce 
>perimeter infiltration rate of the building. I 
>am not quit sure if I need to reduce the 
>perimeter infiltration rate in the simulation. 
>If, it does, how many percentage of infiltration rate do I need to reduce?
>
>Question 2:
>
>Does eQuest programmer has already considered 
>this issue and changed the perimeter 
>infiltration rate automatically with changing 
>window glass type and insulation of the windows?
>
>Yingqi Chen
>
>The PERTAN Group
>44 Main Street, Suite
>Champaign, IL 61820
>
>217-356-1348 ext 205
>
>_______________________________________________
>Equest-users mailing list
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><mailto:EQUEST-USERS-UNSUBSCRIBE at ONEBUILDING.ORG>EQUEST-USERS-UNSUBSCRIBE at ONEBUILDING.ORG
>
>
>
>--
>Carol Gardner PE
>
>
>---------- Forwarded message ----------
>From: Nick Caton <<mailto:ncaton at smithboucher.com>ncaton at smithboucher.com>
>To: Alex Krickx 
><<mailto:akrickx at seriousmaterials.com>akrickx at seriousmaterials.com>, 
>"<mailto:equest-users at lists.onebuilding.org>equest-users at lists.onebuilding.org" 
><<mailto:equest-users at lists.onebuilding.org>equest-users at lists.onebuilding.org>
>Date: Mon, 8 Mar 2010 16:47:48 -0800
>Subject: RE: [Equest-users] Modeling Infiltration and Windows
>I’ve done exactly that in the past for the exactly the same purpose!
>
>The only difference is I believe I always punch 
>in the differences in the metric of ACH.  ASHRAE 
>fundamentals provides some guidance regarding 
>air change rates to expect for various classes 
>of construction as a function of outdoor design 
>temperature, and that was the best I could base 
>my existing construction off of from what info I had available.
>
>Come up with a  “leakiness” for both you 
>construction, old and new windows, and do the weighted average jig =).
>
>Kudos on your fancy facade spelling also ;)!
>
>~Nick
>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 @ 
><http://www.smithboucher.com>www.smithboucher.com
>
>From: 
><mailto:equest-users-bounces at lists.onebuilding.org>equest-users-bounces at lists.onebuilding.org 
>[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Alex Krickx
>Sent: Monday, March 08, 2010 6:05 PM
>To: 
><mailto:equest-users at lists.onebuilding.org>equest-users at lists.onebuilding.org
>Subject: [Equest-users] Modeling Infiltration and Windows
>
>Hello all,
>
>I am interested in modeling the energy savings 
>that occurs when windows are replaced with 
>lower-infiltration alternatives. In the wizard 
>mode, the only place that I see infiltration is 
>under the “Building Envelope Constructions”  Screen.
>
>I’m hoping someone can confirm my methodology:
>
>Can I input a weighted average of window and 
>wall air infiltration here?  If I’m looking at a 
>building with 20% Window to Wall Ratio, and the 
>windows have 0.1 CFM/ft² while the walls have 
>0.04 CFM/ft²can I apply an area weighted average 
>into this box? I would take (20%*0.1+80%*0.04) 
>as the façade infiltration value.
>
>That way I could use the same formula to 
>determine the area weighted infiltration of the 
>façade if better windows were installed.
>
>How do other people model this?
>
>Thanks in advance!
>
>Alex Krickx
>
>
>Alex Krickx
>Building Energy Specialist
>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.
>
>
>
>
>
>
>--
>Carol Gardner PE
>
>
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Chris Jones
14 Oneida Avenue
Toronto, ON M5J 2E3.
Tel.  416-203-7465
Fax. 416-946-1005

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