How far is a return grill effective?

[Designer_82]

Say I have an enclosed office building floor, maybe it is 30,000 sq.ft. maybe the room is 250' x 120'

Let's say I have one supply register on one end of the room and a return grill on the other end, would the air actually travel 250'?

Thanks

 

[EnergyProfessional]

If you dump all cold air in one end, and return the other, one problem will be to find a diffuser and grille large enough. the other problem is, where th diffuser is, it will be really cold and gradually it will get warmer as the air picks up heat.

Maybe people can move their desk based on how cold or hot they like it?

What most offices would do is to have multiple diffuser in areas where you expect people to spend a lot of time (i.e. desks). and place return grilles at locations that don't have a lot of cooling load (those just get cooled by the average room temp air).
You don't want return (low pressure) too close to diffusers (high pressure) since the air would just go the path of least resistance and wouldn't detour through the people.

It is a bit of an art with science. I recommend reading up on some Price and other manufacturer literature for VAV systems etc.

 

[MintJulep]

Yes, the air would travel from supply to return.

It will not travel the way you should hope it will.

It will not have the desired effect of creating comfort.

 

[EnergyProfessional]

MintJulep:

they cram employees in a 250' x 120' room.... I don't think employee comfort and happiness is their goal

 

[IRstuff]

Open floor plan is a thing; Facebook's two largest buildings in the Bay Area are each about a mile long and as far as I have ever been able to determine, walled rooms are mostly for meeting rooms, while workers have their computer stations out in the open.

https://xlab.aud.ucla.edu/workhouse...y-workplace/nytimes-_-facebook-hq-menlo-park/

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

faq731-376 forum1529 Entire Forum list

http://www.eng-tips.com/forumlist.cfm

 

[EnergyProfessional]

Note: multiple diffusers

Looks like a temporary space with all the conduits/wires dangling from the ceiling. Did anyone plan this, or did it just happen over time as they added employees? The noise would kill me. I bet after the picture was taken, everyone put their noise-cancelling ear buds back on.

 

[IRstuff]

That's normal; I've been in that building at least a dozen times and it's always been like that, fixture-wise, anyway. The people standing around yakking is not normal, I think, They've got dozens of small meeting rooms along the middle of the building and walls for that sort of thing, or even for hiding out.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

faq731-376 forum1529 Entire Forum list

http://www.eng-tips.com/forumlist.cfm