Concentric diffusers box

[emalsyd]

Just got hired to install the HVAC at a arcade/gaming facility. The engineer designed most of the rooftop units to utilize concentric diffusers. The owner let the engineer go a while back so I don't have him to ask. Took a walkthrough of the facility today. Most areas are 21' to the roof deck with no ceilings. What's the max height I should install the concentric diffusers. Mostly see them in department stores in drop ceilings as 12-14' height so was thinking 14' would be a max height I'd want to install them? I'm afraid if we went much higher, the heat wouldn't get down to the floor level. Also trying to convince the owner to install paddle fans to help push some of the hot air down.

 

[chicopee]

Are these rooftop units for heating and cooling?
I have not looked at these diffusers for a long time, so I would try is to contact the manufacturer catalog to determine the effective distances of their product. Adding a suspended ceiling and/or having long drops would be helpful.