Laundromat Make-Up Air.

[MechGuy22]

Hi everyone, working on a Laundromat, first time doing a new one. Each of the dryers exhausts 200CFM of air while running, the only thing is that I have 20 of these things in a 1500 sq ft space. This will equate to 2000 CFM of makeup air without even accounting for ventilation for the space. How do people do this? With that amount of makeup air I would need an outside air unit which the owner could never afford. I was thinking that maybe the intake air could be ducted to an open room separate from the space perhaps?

Thanks!

 

[berkshire]

Npstewart,
The most common method is to place the dryers in a wall inside the laundromat. Bring in the makeup air behind this wall un tempered. Be sure to put plenty of clean out doors in the exhaust duct from the dryers, so you can get the lint out later.
B.E.

The good engineer does not need to memorize every formula; he just needs to know where he can find them when he needs them. Old professor

 

[317069]

- NFPA will help your calculation
- do it in right way and don't worry about owner

 

[MechGuy22]

Thanks for the suggestions.

I basically made the room behind the dryers enclosed. Then I showed (3) large GRV units. I had the architect insulate the common wall between the room and laundromat. I sized the GRV units to handle 10,000 CFM between the 3 of them. I figured the air can be pulled directly in the room via the ceiling mounted GRV unit.

Again, thanks for the help!

 

[cdxx139]

Berk, what a great low cost design, I have always used makeup air units, and these systems always caused my the greatest headaches with architects. (because of duct size and makeup air unit etc.

So you provide untempered to the plenum behind the laundry units? Then provide grilles low and behind the dryers, so they pull from the plenum?

I assume you dont heat the plenum, but wuill need extra heat in the laundry room becasue all that untempered air can get very cold.

knowledge is power

 

[berkshire]

cdxx139 (Mechanical)
The main thing is to keep the Plenum isolated from the main laundry room. The dryers will pull some air from the main room at the front through leaking door seals. But the majority of the air will be pulled through the back straight into the dryers.
Another thing to bear in mind is that I am at latitude 35 so this may not work because of condensation and dewpoints in more northerly climes.
B.E.

The good engineer does not need to memorize every formula; he just needs to know where he can find them when he needs them. Old professor