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: 5459

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

Featured Forum Discussions

Too many BTU's. Too much horsepower?

Started by Steve in General Forum. Last reply by Walter Ahlgrim 58 minutes ago. 3 Replies

Stack/wind pressure and flow networks.

Started by Daniel James Grundy in Training. Last reply by Daniel James Grundy 5 hours ago. 5 Replies

BDT with vermiculite in hollow CMU walls?

Started by Brad Cook in General Forum. Last reply by John Nicholas 11 hours ago. 2 Replies

Strange IR Image

Started by Larry Nissman in General Forum. Last reply by Brad Cook Mar 9. 7 Replies

Videos

  • Add Videos
  • View All

Latest Activity

Walter Ahlgrim replied to Steve's discussion Too many BTU's. Too much horsepower?
"The 5 ton system you have is not 500 hp racecar engines they are 500 hp truck engines. The duct…"
58 minutes ago
Daniel James Grundy replied to Daniel James Grundy's discussion Stack/wind pressure and flow networks.
"So I wanted to start with a basic who can help then go into more detail later. But yes find…"
5 hours ago
Daniel James Grundy replied to Daniel James Grundy's discussion Stack/wind pressure and flow networks.
"My tutor got back to me and while areas don't quite feel right a little to much assumptions…"
5 hours ago
Brennan Less replied to Daniel James Grundy's discussion Stack/wind pressure and flow networks.
"Daniel, I'm assuming you're trying to predict the airflows through the different openings…"
7 hours ago
Martin Newmark joined allen p tanner's group
Thumbnail

Energy Auditing Equipment for Sale, Trade or to Purchase

Discuss the pros and cons of the equipment you are interested in prior to purchase. Post equipment…See More
9 hours ago
John Nicholas replied to Brad Cook's discussion BDT with vermiculite in hollow CMU walls?
"If the drywall is in good shape, you should have little worries about the 50pa depressurization…"
11 hours ago
tedkidd replied to Steve's discussion Too many BTU's. Too much horsepower?
"Does the house ever feel clammy? Do you have to keep the thermostat below 74 to be comfortable? Is…"
13 hours ago
Danielle Sass Byrnett liked Diane Chojnowski's blog post Don MacOdrum receives BPI's 2017 Tony Woods Award!
14 hours ago

Home Energy Pros

Welcome to Home Energy Pros – the unique digital community by and for those who work in the home energy performance arena.

Home Energy Pros was founded by the developers of Home Energy Saver Pro (supported by the U.S. Department of Energy) and brought to you in partnership with Home Energy magazine.  Home Energy Pros is sponsored by the Better Buildings Residential Network. Please honor our Guidelines

© 2017   Created by Lawrence Berkeley National Laboratory.   Powered by

Badges  |  Report an Issue  |  Terms of Service