Greetings

First of all......

* As we upgrade and build new....

  I think it is time to eliminate atmospherically vented appliances from the breathing zones of our homes

* I realize that the effects of wind and mechanical equipment can and often do overwhelm Stack Effect.

 

My current favorite online resources for visualizing "Stack Effect" are.....

*John Straube's Article

http://www.buildingscience.com/documents/digests/bsd-014-air-flow-c...

 

*John Klote's Article

http://fire.nist.gov/bfrlpubs/fire91/PDF/f91013.pdf

 

*Bud Poll's Worksheet

http://myenergyworkshop.homestead.com/hot-air.html

 

I plan to post some Illustrations and see if you folks agree with my current thinking about the location of Neutral Pressure Planes

Meanwhile...

Does anyone else have suggestions for online links concerning  "Stack Effect"?

Views: 4324

Reply to This

Replies to This Discussion

An important element of the Klote report is that he uses a simplifying formula that only approximates the typical multiple vertical opening model.

"Analytic equations have been developed for the location of the neutral pressure plane for a few simple cases of leakage openings. However, the combinations of leakage openings in building shafts and compartments can be very complex... Analysis is simpler for horizontal openings, because the pressure difference across the opening does not vary with elevation. The analysis of this section is for horizontal openings…Vertical vents can be approximated by horizontal vents when the height of each vent is small compared to the height of the air column."

In a 2500 SF house with 1 ACH50 (about 350 CFM50), the Effective Leakage Area (ELA @ 4 Pa) is about 8 square inches. Since the blower door test is conducted with deliberate leaks sealed, this envelope leakage area is similar to what we might expect from dampered mechanical openings, making both deliberate and accidental leakage areas equally significant.

I'm still not sure what you're trying to accomplish by "controlling" the height of the NPP, especially given that - as you attest - the actual NPP will vary with both wind and mechanical effects.

Here's another link to an old article, CBD-23. Air Leakage in Buildings, from the National Research Council of Canada:

http://archive.nrc-cnrc.gc.ca/eng/ibp/irc/cbd/building-digest-23.html

RSS

Home Energy Pros

Home Energy Pros was founded by the developers of Home Energy Saver Pro (sponsored by the U.S. Department of Energy,) and brought to you in partnership with Home Energy magazine.

Latest Activity

Susan E. Buchan posted a status
"EEBA's Conference in St. Louis last week was a great success! Presentations at http://www.eeba.org/conference/2014-presentations."
14 hours ago
Jan Green replied to George Kopf's discussion Real Estate Professionals need our support - but how?
"It helps for companies to understand what the public wants and to educate them so that realtors are…"
14 hours ago
Hal Skinner replied to Hal Skinner's discussion An example of what an RCC can do with no R- insulation in the walls.
"Hi Bret and thans for the offer.   I sent you a friend request so I can send you a…"
14 hours ago
Kevin Jordan shared George Kopf's discussion on Facebook
14 hours ago
Kevin Jordan replied to George Kopf's discussion Real Estate Professionals need our support - but how?
"so who funds the greening of the inventory? would this be company by company?"
14 hours ago
Don Fitchett commented on Home Energy Magazine's blog post A Day in the Life of Learning
"This is a great addition to the July edition. Our PLC training uses the three areas too, but more…"
14 hours ago
Bret Curry replied to Hal Skinner's discussion An example of what an RCC can do with no R- insulation in the walls.
"Hal, Not sure if you serve the Little Rock market, or know of a company who does. If you know of…"
15 hours ago
Robert Cameron's discussion was featured

Air duct testing questions.

Many towns are now adopting the 2012 code about duct testing.  This is a great thing. However I…See More
15 hours ago

© 2014   Created by Lawrence Berkeley National Laboratory.

Badges  |  Report an Issue  |  Terms of Service