sundance-communications.com/forum Forums Wiring - Telecom Carriers - Trunks & Services Cabling Telephones Systems Wiring Removing Heat from Comm room

This maybe the wrong board for this.

I am no HVAC specialist. I did have a local A/C guy take a look at the small room that is in use to say he thinks it's more of a heat removal issue than a cooling issue.

Anyone know of an exhaust fan that's being used in some comm room far far away?

The closet is 10 foot high x 42 inches wide x 25 inches deep. Around 75 cubic feet?

Inside is a Dell PowerEdge 2900, small clone Linux box, DSL modem, Linksys router, Linksys 24 port switch, 1 fiber to copper transceiver, and 1 RCA to Coax converter.

I'm seeing that Dell Server can put out 3200 BTUs per hour (running full blast). I spec'ed this one out at about 2400 - 2500 BTU.

I'm envisioning a small exhaust fan that pump this hot air into the drop ceiling.

Anyone? :shrug:

I've got a comm closet 4x4x12. I have a few servers on a rolling rack, and then the network and phones on a small backboard over the doorway. I mounted a standard 5000 BTU electronic-controlled AC through the wall into the drop ceiling of the mens room next door. It's set to 69 degrees in Economy mode, which means if it ever actually detected that the temperature actually was 69 degrees, it would shut off until it climbed back up... I don't think it's ever off. It's passable, temp wise, no clue about whether or not it breaks any "rules".

I'm envisioning a small exhaust fan that pump this hot air into the drop ceiling.

I've done exactly that. Only you will need more than a small blower, I used (I think) a 500 cfm. It will need to run all the time. Remember that you will need to pull air up through the closet. I used a louvered door, put a 30x30" furnace filter over the bottom on the inside and blocked the top off with a piece of plywood. Cool air is drawn in the bottom and out into the ceiling. It is also a good idea to keep the bottom of the rack open for maybe 8 inches so air can enter. You will want to weatherstrip the door and change the filter regularly, it gets filthy. HVAC supply houses have frames that will hold the replaceable filters that you can use to attach the filter to the door.

I did have a local A/C guy take a look at the small room that is in use to say he thinks it's more of a heat removal issue than a cooling issue.

I agree. You really don't need a separate AC unless the ambient air outside the closet is unconditioned. Also, the problem with using an AC is getting the air to circulate and hot air drawn back into the AC. They work fine for rooms but with a rack in a small space, unless you can get it to blow into the bottom and return from the top you are going to have hotspots.

Nowhere should it exceed 85 deg. so when you design your system spend a few bucks on digital thermometer with a remote probe to check.

-Hal

Have you tried just placing a fan in the closet to circulate the air? Is there a vent in the door? If you use an exhaust fan, you'll be constantly sucking the conditioned air up into the attic.

Have you tried just placing a fan in the closet to circulate the air?

Tried that. It does very little.

Is there a vent in the door? If you use an exhaust fan, you'll be constantly sucking the conditioned air up into the attic.

That is the idea. Matter of fact if the space above the ceiling is used for return air that's the way it's supposed to work. Your blower is just helping it. If it's not used for the return so what. If that's a problem you can always have an HVAC guy fabricate some duct work to send it back into the conditioned space.

-Hal

Thanks for all the replies. Some how I'm not getting email notification when a reply to the topic is made?!!?

So I should remove the A/C sending duct/vent from the top that is in the room?

Focus more on getting cool air in from the bottom and flowing to the top because obviously we all know that hot air rises.

Hal, any idea where you got that blower device? 500 CFM sounds pretty loud right? This is a dentist's office =)

Broan L400, actually it's 434cfm. Grainger stocks them. Very quiet low speed cabinet blower. If you install it right (I used rubber vibration mounts, also from Grainger, to keep the "hum" down by isolating it from the ceiling)it won't be any louder than any of the other HVAC vents. All you will hear is the air.

-Hal

Something to think about here. I've been in a couple of municipalities whose FD's would NOT allow vents in the doors, or returns to the HVAC, because the plans called the area "Utility Room". They had the attitude that Utility Room meant electrical panel room and you couldn't tell them otherwise. These were motels, and the GC told me that once the finals were done, he would cut vents in the bottom of the door and above the door frame for some convection cooling. One was close enough that I was able to check it a couple of years later and all was 'cool'. Then there was the one that was on the west wall with the only access through the pool equipment room. HEAT AND HUMIDITY! I told them that we couldn't warranty that one unless they put in AC. So, after the system went down from overheat three days in July, (Central KS) they put a 10,000 BTU thru a hole in the wall, and a little roof over the unit, so the sun wasn't beating straight on it. John C. (Not Garand)

Something to think about here. I've been in a couple of municipalities whose FD's would NOT allow vents in the doors, or returns to the HVAC, because the plans called the area "Utility Room". They had the attitude that Utility Room meant electrical panel room and you couldn't tell them otherwise.

Well yeah, if you have fire rated doors then there can be no louvers or even glass. There are ways to condition such spaces keeping them isolated from the rest of the area but that's only practical with a decent size room. If they are going to classify your small closet as a utility room with those restrictions then you are going to have problems with cooling or removing heat and the thing to do is just not use such a small space.

-Hal