return air outlet location

[sunsatwik]

how to fix the return air outlet location with respect to supply air outlet? what the factors are kept in mind while deciding the location?

 

[RandomUserName]

Depends on the type of air distribution system: fully mixed, partially mixed (UFAD), or stratified (Displacement Ventilation).

2015 ASHRAE Handbook - HVAC Applications chapter 57: Room Air Distribution will have everything you need to know. It is 18 pages long.

For the most part, return air outlets can be placed anywhere in relation to supply air outlets with little issue. Return air outlets affect room air motion only immediately (within a couple of inches) of their outlets. Every room with a supply outlet should have a return outlet. If the distribution design is UFAD or DV, it can be advantageous to locate return air outlets above heat generating items and in the highest points of the ceiling. Short-circuiting is pretty minimal in general as well. I personally like to place a return above my zone thermostat.

 

[cry22]

Don't forget that you cannot return air from one room through another room (code violation) - i.e do not transfer air from rooms and return from the corridor (common mistake). Cannot use any room as a return air plenum.