Exposed ducting and air diffusers elevation AFF

[Golestan]

I am looking for an optimum elevation AFF for round air diffusers. The space is a retail store with exposed ducts and 18 ft. high roof deck all open.

I want to keep the top layers of air stagnate (near the roof), and keep the lower occupied zone conditioned. Diffuser throw is about 15 ft.

Thanks for any comments.

 

[GMcD]

You should use a low level displacement supply air system if you want to do that. Supplying air from overhead is designed to create fully mixed air conditions in the room. You might get a little stratification if you use diffusers to "throw" the fresh supply air down to the occupied level, but that jet of air acts like a "jet-pump" and entrains the stratified stale air in the airflow pattern. You "might" be able to use some adjustable nozzle air outlets at high level to get some air down to the floor while minimizing the mixing - look at the Seiho brand or Air Concepts nozzles in panels:

http://www.airconceptsinc.com/products/punkah/apl-panel.html