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Equipment Closet Cooling

post #1 of 8
Thread Starter 
I'm in the process of converting a closet (under the stairs) to an equipment closet. I've only put in one server and a UPS and it's already getting too hot so I need to devise a cooling solution. I was wondering what you guys recommend.
I can run an HVAC return from the closet to my return plenum. The problem I'm thinking of with that is that the AC will only turn on intermittently giving plenty of time for temperatures to rise.
I saw this in another thread by cheezit73 where he put in fans to suck air out. I could use either that or the bathroom vent vans recommended.

What would be the optimal way to exhaust? HVAC Return? Jumper (w/fans) to next room. HVAC Return w/fans (would that cause problems on the HVAC heating up).
Also regarding air pressure issues , I don't want to cut the door (keep fan noise inside the closet) but could run a supply line from the AC or cut a hole in the stairs and put a vent there
post #2 of 8
As you suspect, you can't rely on just a normal HVAC supply to cool the equipment, since the closet will need cooling 24/7 year-round, regardless of the needs of the rooms around it.

I used this:


To actively vent to the HVAC return, which works well, except that even with an HVAC supply in that closet, there's not enough fresh air drawn in to support the full cooling capacity. As I've got no easy/pleasant way to add a intake grill, I just leave the door cracked...

I definitely recommend getting a vent somewhere to allow adequate airflow in...

post #3 of 8
First finalize what components your going to conceivably put in there.

Read up and find their power draw.

You can take the max wattage of power draw and calculate how many btus that conversion will produce.

Then calculate how many cfm you need to provide to mitigate the heat produced.

Then look at solutions.

As far as ventilators there are some good turn key solutions out there which are thermostatically controlled variable speed ventilation systems. They are a bit pricey but work well for your situation. Active Thermal Management is a company that comes to mind as well as Middle Atlantic.

If your into DIY and piecing your stuff together the Panasonic in-line ventilators are well regarded.
post #4 of 8
I used one of these along with a couple spare 120mm fans I had for a built-in I made. Works pretty well.

post #5 of 8
Thread Starter 
Roughly upsized I'd say 4KW. I'm not sure how much that should translate into from a CFM / Heat perspective. I also wanted to run a secondary duct over my projector (350W) as well.
Essentially get a 6" duct running above the projector and a 6" running from the HVAC closet , merging to an 8" via a wye then to the return plenum.

Inline Fan with thermostat fan switch in the closet to trigger it
Option 1) Run the inline fan at the 8" line. The Panasonic you mentioned was a 6" so not sure if that would work or if there's a similar quiet 8" version that's also recommended.
Option 2) Use the 6" Panasonic inline fan on the closet line before the 8-6-6 wye. Not sure if there's any consequences on the projector line. (Hot air flowing to the projector instead of the plenum, could use something like this)
Option 3) Run two separate lines to the Plenum (I'd rather minimize the amount of damage I'd be inflicting on the Plenum, so would much rather not do it this way)

Fan in the vent
Option 4) Use the fans that Cheezit used (Cooler Master 60 cfm x 2) at the closet grill. Same problem as option 2 at the wye merge.

All of those seem like they would work, not sure what would be best.
Thanks for all the help smile.gif

For reference:
Marantz SR6006 @ 650W
Emotiva XPA5 @ 1000W
1 File Server @ 800 W
1 HTPC @ 600W
1 STB @ 35 Watts
2 UPS (1500 Watt but think they'd have low power consumption themselves) ~ 100W (complete guess)
Giving a grand total of 3185 watts, upsizing to 4kw for future unknowns

Sorry one more Question
I was looking at ways to silence sound transmission through the duct so that it doesn't reach upstairs and ran across this
My concern was being internally insulated and having a whole house humidifier it would eventually grow mold. Is there any other similar item that would work better or should I use this and count on changing it out every year or two. Also is there any benefit to using insulated flex-duct instead of regular non-insulated for sound dampening
Edited by syyid - 11/29/12 at 10:26pm
post #6 of 8
Hi Syyid,

Some have used that thermostat with success in this application.

I toyed with using one fan for both rack and projector. I ended up with a independent fan each. The rack calls for vent a few times a day in summer and I didn't want to pull air through projector when not needed.

Look at filtration for the air going into the equipment closet, you'll be pulling a large amount of dust through there if not.

A correctly sized flex insulated duct should not produce much sound outside the system in another room. Now in the equipment closet you might have some turbulence noise at the inlet and outlet, but I'd address that with some dead vent design instead instead of that muffler. Insulated flex duct is quieter outside the system(adjacent rooms) but less efficient in terms of cfm capability.

Now sizing and cfm requirements

Its pretty common to assume a 20% constant load for the wattage ratings of the components.

So 0.20*4000= 800Watts constant load approx.

A reasonable multiplier for heat production per watt is 3.42 btu/hr/ watt, So 3.42*800= 2736btus/hr Waste Heat

From that look at this chart and help you decide how much ventilation you need. This chart is for a Middle Atlantic closed rack type system but should give some useful guidance as to the ventilation requirements. Based on looking at your equipment and the calcs and my own experience with the panasonic fans I would recommend 120-240cfm. I don't think you would need anything over 240 as thats what I use and its overkill for my rack, but you can slow them down with ceiling fan speed controllers, so thats always an option. If your interested I detailed my own journey with the fans in my build thread(See Sig):

post #7 of 8
I had considered putting an old range hood in the ceiling of my closet, any thoughts as to the feasibility?
post #8 of 8
I'd be concerned with noise. My range hood is fairly loud.
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