Laundry room design question.

[DuctHunter]

I think I posted this thread in the wrong place the first time.

I am designing a four story hotel with a commercial laundry room on the first floor.

We were given a prototype design to follow, but the problem is the prototype was designed for Atlanta and the hotel is located in Michigan. The gas dryers for the laundry room will require a maximum of 2400 cfm of make-up air (assuming all dryers are running at the same time..600 cfm per dryer). We can't make-up the air from the corridors or building interior because we are only using small fan coil units to ventilate the core office spaces with 80 cfm of outside air here and there. Plus the dryer manufacturer prefers the air make-up directly from the outdoors. In the Atlanta prototype they are making up the dryer exhaust air directly from the outdoors via louvers without any tempering whatsoever. The winter design temperature in Michigan is -13 deg F so the air must be tempered somehow. I think it should even be cooled in the summer time from 90 degrees.

Even heating 2400 cfm to 40 degrees will require 130 MBH of heat.
There will be boilers available for hot water heating, but I don't know what the best way to temper the make-up air for the dryers in the winter time and summer time is without over complicating it.

Anybody have any experience with this ?

Thanks for your help.

 

[MintJulep]

thread403-321168

Cooling make-up air for driers in the summer is just silly.

 

[DuctHunter]

So what about heating it in the winter ?

 

[317069]

"In the Atlanta prototype they are making up the dryer exhaust air directly from the outdoors via louvers without any tempering"
what is the winter outside design temperature, is it 15C or more.
you can check the prototype again or if you can check any laundry mat in Michigan to see how they work.

 

[berkshire]

cdmac122395
Atlanta gets very few days where the temperature is cold, they will get a sweeping cold from the north where it will freeze for two or three days, then the temperature will be back up around 15 to 18 degrees C again.
Do not temper the incoming air on hot days, send it straight to the dryer. Recognizing that in Michigan the air may be coming in as low as -18 c or less you, would need to look at what the dryer unit can handle for incoming air, before looking at tempering. Also I am assuming this is a hotel laundry for bedclothes, sheets , pillowcases, towels, and whatever, not a Laundromat for customer use. In which case you should be using direct insulated ducting for the supply air to the dryer, not a louver in the wall which even with the heat generated in a laundry room will result in complaints about the cold. . The dryer bank in a screening wall that I mentioned in the post mint julep linked to will only work, if you can lay out the laundry room that way. That was a commercial hotel laundry with four big dryers and a lint separator behind a partition wall. It sounds like your layout has already been done for you.
B.E.

You are judged not by what you know, but by what you can do.

 

[317069]

Laundromat is also a commercial laundry, not a residential, and in a hotel laundry room, there are employees working there, the Code didn't distinguish between an employee and a customer.
if we can apply a good solution in a hotel laundry then we can apply it in a Laundromat too.

 

[dbill74]

Does the prototype include space heaters for the laundry room? If so, I think you'd be fine following the prototype adding backdraft dampers to close the louvers when the dryers are not in use. A plenum as suggested in Mintjulep's post is a good idea also.

If space heaters are not in the prototype, add them. From the way the OP put the question, sounds like occupant comfort is the main concern. As long as you keep the intake louvers close to the dryers, the dryers are going to pull that air in before it has a chance to mix with the rest of the room air. Dampers and/or plenum will help reduce mixing even further.

 

[PEinPA]

Most laundries I see have a walkway behind the dryers where the makeup air can be supplied. I would provide a fan of some sort with electric heat that will heat the air up to 40°-50°. I do not like seeing freezing cold air being provided. The staff will complain that it is too cold to empty or load the dryers. The makeup air fan will run only when a dryer is running. You can get as simple or fancy with the controls as you want. How well the service walkway behind the dryers is sealed from the main room varies a lot.
In the summer you are dumping unconditioned air behind the dryers which is not a problem.

 

[DrRTU]

The chase behind the dryers as posted by PEinPA is correct. Un-tempered air is admitted behind the dryers. Wall mounted louvers with MODs inter-locked to dryers. We have completed numerous hotels with this design and we are located near Chicago. Check the hotel chain prototype BOD booklet you should designing to. FYI the chase should not be considered an occupied space by an AHJ, if it were, then tempered makeup air would be required.

 

[317069]

if we introduce a -20F cold air into the dryer, does it effect dryer performance itself or it is normal operation for dryers?
if it does not effect, then why don't we see what I can call as a direct vent dryer like direct vent furnace