[Equest-users] Modeling Infiltration and Windows

[Nick Caton]

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

 

 

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: 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: 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

 

1250 Elko Dr, Sunnyvale, CA 94089

(t) 408.541.8124

 

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