high rise bldg laundry
10 ton dedicated rtu serves the room Currently balanced to 3200 cfm.
This unit can only do 800cfm oa (per model number)
Dryer vents tied to two headers (set of 3 dryers each). First grille on header is return air from room It is balanced to 1600 cfm.
A backdraft damper is used to reduce the air to 1100, 600 and then 100 cfm through the grille as each dryer comes on.
2 return grilles back to rtu,
2 headers combine to inlet of an exhaust fan at 3200 cfm
The RTU should be able to bring in 3200 CFM of oa, in order for the system to work when all dryers are running.
There is no transfer duct to the room from adjacent spaces. The room door from elev lobby is open so some air can flow in. Other side of elevator lobby is swimming pool. No offices, or apartments to transfer air from.
1. Should the RTU be replaced with 3200 cfm OA unit? That will be costly.
2. All return will have to be exhausted to the outdoors if all 6 dryers are running. In this case the RTU will only be able to heat the air to 60 degf in winter and have a coil discharge of 70F and not 55F in summer. OA at 95/78 and 10 for summer/winter
Can the system work without increasing the OA?
Worst case: Can the air only be heated in winter and not cooled in summer fully to save energy? Let the room temp go to 85 or 90 in summer.