Reposted from i.e., the Center for Energy and Environment's Innovation Exchange blog -- http://mncee.org/Innovation-Exchange/ie/

 

Even though the walls of an apartment look solid, air buoyancy and pressure differences between interior spaces cause air to move between rooms and even to other units in the building. And as it travels within a building, air pollutants such as secondhand smoke (SHS) can find their way from one unit to another. Stack, wind, and exhaust fan effects are all interior air driving forces that affect the migration of SHS within a multifamily apartment building.

In winter, for instance, the heated air inside the building has a lower density than the colder outside air. Think about a hot air balloon: warm air rises. Because of its buoyancy, the warm indoor air tends to rise and escape out of the top of the building. This air movement draws cold outside air in through the lower part of the building. Watch the Winter Stack Effect animation below to see how as the interior air rises, SHS migrates with it from lower to upper apartment units.



In summer, the opposite airflow occurs. The conditioned indoor air is cooler and denser, and therefore tends to flow towards the lower half of the building. Warm outside air is drawn into the upper half of the building. As you can see in the Summer Stack Effect visualization below, the interior air movement entrains SHS from higher to lower units.



Whatever the temperature, when air flows from a high pressure area to a lower pressure area, it creates wind. And when wind impinges on a building, the interior air tends to flow from the windward side to the leeward side, i.e. from high pressure to low pressure. Our Wind Effect animation shows how air carries SHS as wind pushes it from one unit to an adjoining unit.



In addition to the weather, mechanical factors can affect indoor air movement. In the next animation, you can watch as an exhaust fan sucks air out of a room, mechanically lowering its pressure. This create a pressure difference between the room and its surrounding areas. Since air flows from high pressure to low pressure spaces, air from the adjoining rooms is drawn into the room where the exhaust fan is running. Our final visualization shows how the Exhaust Fan Effect can entrain SHS from an adjoining unit below.



We hope that our animations will improve your understanding of the air driving forces in buildings and how they affect secondhand smoke transfer between apartments. Feel free to link to or embed these videos from this blog post, our resource page, or our YouTube site.

The motion graphics animations were designed and produced by Huma Saqib.

Related posts:
> 1,000 Words: Combi System Animations

Indoor Air Quality and Energy Efficiency: Part 1

Views: 268

Comment

You need to be a member of Home Energy Pros to add comments!

Join Home Energy Pros

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

Bob Mariani 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
3 hours ago
Bob Mariani replied to William Parlapiano's discussion Equipment for Sale Updated April 9, 2015 in the group Energy Auditing Equipment for Sale, Trade or to Purchase
"I would be interested in a package deal for the items marked as "Available"  Email…"
3 hours ago
Steven Lewis replied to William Fisher's discussion Can tankless water heaters provide hot water even when the groundwater is fairly cold?
"Look at reducing the ambient humidity in the home.  The dew point is the key to the…"
yesterday
Olivia Taylor posted blog posts
Friday
norman farwell replied to Bryan Pringle's discussion Dense packed cellulose in basement?
"Ha, we're on the same wavelength.  That's the big question--I'm still thinking…"
Thursday
Bryan Pringle replied to Bryan Pringle's discussion Dense packed cellulose in basement?
"Thanks Norm, we'll have a couple of case studies when all is said and done. Just curious, do…"
Thursday
norman farwell replied to Bryan Pringle's discussion Dense packed cellulose in basement?
"Bryan,  I am trying the same thing for most of the same reasons and also against advice to the…"
Thursday
Morgan M Audetat commented on Sean McLoughlin's blog post Programming in-floor electric radiant heat, is it worth it?
"You would need a large bathroom to see the difference. We install them both ways depending on the…"
Thursday

© 2015   Created by Lawrence Berkeley National Laboratory.

Badges  |  Report an Issue  |  Terms of Service