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: 4263

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

William H Nickerson commented on Brandon Walton's blog post 12 Things Every Home Performance Contractor Should Have on Their Work Truck
"One more thing...you need a little more bend in that cap"
30 minutes ago
Tom Mallard replied to Hal Skinner's discussion Rooftop A/C units and exposed ductwork in the group Radiant Control Coatings
"Sounds like the perfect, thin insulator adding enough thermal inertia to separate two masses and/or…"
43 minutes ago
Hal Skinner replied to Hal Skinner's discussion Rooftop A/C units and exposed ductwork in the group Radiant Control Coatings
"OK Tom, I think I am on the last questionow,,,I think.  LOL Going under the building and…"
2 hours ago
Hal Skinner replied to Hal Skinner's discussion Rooftop A/C units and exposed ductwork in the group Radiant Control Coatings
"Tom, sorry for having to break this up but my responses I guess are too long. You talking about the…"
2 hours ago
Hal Skinner replied to Hal Skinner's discussion Rooftop A/C units and exposed ductwork in the group Radiant Control Coatings
" "
4 hours ago
Hal Skinner replied to Hal Skinner's discussion Rooftop A/C units and exposed ductwork in the group Radiant Control Coatings
"I guess I got too mlong winded ther, it cut me off. 1.  Spray the coating on the ducts, plenum…"
4 hours ago
Kurt Shafer replied to Tom Conlon's discussion Whole House Fans - Love 'Em or Not?
"Jan, Here are some facts. the 30 inch fan from Home Depot (not one I would recommend) is rated at…"
4 hours ago
Hal Skinner replied to Hal Skinner's discussion Rooftop A/C units and exposed ductwork in the group Radiant Control Coatings
"Hi Tom. It looks like I will have to start off most of my answers to questions with this…"
4 hours ago
Everblue posted a video

Retrofitting Your Home for Energy Efficiency

Building Science: What is an Energy Audit? Using a Blower Door Test. Retrofitting Your Home for Energy Efficiency
5 hours ago
Profile IconTimothy Blair and Tomás León joined Home Energy Pros
5 hours ago
Home Energy Magazine's discussion was featured

Let's Talk Gender

It’s no secret that home performance is a male-dominated industry. Attend any industry conference…See More
5 hours ago
Diane Chojnowski replied to Home Energy Magazine's discussion Let's Talk Gender
"ACI has a webpage for their Women in Home Performance initiative:…"
5 hours ago

© 2014   Created by Lawrence Berkeley National Laboratory.

Badges  |  Report an Issue  |  Terms of Service