Is it possible to design the supply and return air from same grill...?

[anil130]

hi guys..recently iam going to installed ductable unit and for supply air there will be no problem but for return air there is no space so is it possible to design the supply and return air from same grill...?

[Emmett]

I have an area in a industrial building that used this concept 60 years ago, the single duct provides supply air on the outside and internal duct provided return. This system does not work very well the supply air tends to short cycle right back into the return. I think if it were reversed it might have worked better supply on the internal duct and return on the outside, assuming you have enough throw. Again you have to avoid short cycling the air. I tried to find commercially available duct like I am descibing but was unable to find a source for them. I know someonw used to make it, I have only seen this in one place and suspect they quit manufacturing.

[Brian_UK]

Not suggesting that you buy these units but they are made.

http://www.troxuk.co.uk/xpool/download/en/technical_documents/diffusers/leaflets/t_2_1_2_vsd35_3_az.pdf

[anil130]

@emmit & Brian: many thanks for the reply.here i have attached the file and somehow i have tried to design the return and supply air from same grill...plz do comment if any mistake..6636

[Brian_UK]

Why can you not use a ceiling grille to receive the return air ?

If you are not allowed to use the ceiling then what access do you have for filter and unit maintenance?

[anil130]

@Brian: yaa that may the option...for the unit maintenance like filter and other things there will be trap door just below the unit and from there we can do the maintenance.many thanks for the suggestion..and i will try to design from the ceiling also..

[Brian_UK]

Is it possible to incorporate a return air path through any ceiling mounted light fittings?

[anil130]

@brian : Yaa it is possible...and i am going to do that one...and many thanks.