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A Micro-A/C for a Server Closet?
DiZNoG asks: "I work from home and run two businesses from there. Sick of server and switch noise in my home office, I've been thinking of taking an old hallway closet that used to house the furnace (since moved) and turning it into a literal server closet for my various servers and networking gear. I have 4 servers and various networking gear and even a system for getting everything in and accessible worked out. Bonus, the room already has power and is perfect placement for my access point (already secured, thank you!) However, I am running into problems finding a small air conditioner for the size of room. It's literally 15 sq. ft. and maybe 100-125 cubic feet total. By my estimates that's something on the order of 150-250 BTUs (or less) with the hardware. Does anyone on Slashdot know of micro A/C units to keep such a small area in server friendly temperature efficiently? I did see this homebrew action, but I'm looking for much less maintenance."
The square footage of the space has almost nothing to do with the size of the cooling unit you need. You need to base it on the wattage of the equipment you're going to put in there instead. Divide the wattage of your equipment by three to get an approximation of the BTUs per hour rating you'll need on your AC unit. Regardless, the laws of thermodynamics require that you will have to cut a vent hole for the heat to exit through even if you're using an air conditioner. As long as you're going to have a vent hole anyway, why not cut two? Put a big slow quiet fan in the top one blowing in, and an air filter in the bottom (or the other way around)?
If you insist on AC, you probably want something like this: APC NetworkAIR AP7003 or more likely, some other (cheaper, but similar) portable AC unit with an exhaust hose from your local Wal-Mart.
I'd recommend one of these. The twin fan design can be set to exchange, and the controls can be set to certain temperatures so that you're not wasting energy in the winter.
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If it was used for heating at one time perhaps you could use a fan to fee the air into the ducts in the winter months (assuming your winter months are like my winter months
Trolling is a art,
for a situation just a bit bigger than what you described: http://www.getcozy.com/fff.html. We like it. Here in Seattle we get quite a bit of condensation that needs to be emptied (or pumped if you want). This place also has other options you may wish to look at. Nice guys too.
How about this A/C unit?
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http://www.hvacportablesystems.com/images/210airc
Conversion factor: 1 KWH = 3412 BTU
Multiplying the average (not peak) wattage by 3.4 will get the BTU's per hour of cooling capacity.
My results have been so-so.
First I tried one of the portable units. Two caveats with them:
1. Get one that has TWO ducts, these suck in air through one to cool the condenser ("outside") coil, then blow the hot air out the other. I got one that had just one, which means it uses some of the room air to cool the condenser. Problem is, in my closet, that meant enough air was being sucked into the closet from the rest of the house that the unit effectively never shut off. Not desirable.
2. Be careful where you vent the exhaust. Many models now have a pump that dumps the condensate over the condenser coil to help increase the cooling. This means the exhaust air can be VERY humid, and you probably don't want to just dump that into your attic. (Oops... I did that...) Especially if it's cool outside (thus the attic is cool) you may wind up with a lot of water collecting in the insulation. So vent it outside!
I decided I wasn't happy with the way the portable worked, so I actually installed a mini-split. WAAAY too big for the room (it's 9000 btu and the room's about 6ft square) but with the application of some extra controls (I work for an HVAC controls company) I managed to keep the runtime reasonable.
You may be able to find smaller units - some people have suggested RV units, that might work better. Just be sure to get "low ambient" options if you live where it gets below 60 degrees outside, and you expect to need it during the winter. Otherwise, you'll be replacing the compressor after the first winter. Basic low ambient items are some heat tape wrapped around the compressor and a pressure switch that cycles the outdoor fan.
If your heat levels aren't too bad you might get away with just a bathroom exhaust vent in the ceiling. I bought a combo light/exhaust fan and replaced the closet's light. Installed a line-voltage thermostat on the wall, and now the exhaust fan comes on if the closet gets too hot. Make sure the closet door has a decent gap at the bottom to allow air in. Unfortunately, my heat load was high enough that the fan pretty much ran all the time...
I live in Florida and have a hallway closet serving as a server closet. Currently it has one PC (333 MHz AMD minitower with 4 HDs), my DSL modem, a router, and an access point. In the past it also had a 500 MHz Compaq Deskpro EN SFF (85W PS, I think) and an ancient 120 MHz full-size Compaq Deskpro.
I keep the house at 75-80 degrees, the closet has louvered doors, and heat has almost never been a problem. I ran into an issue once when something was wrong on the AMD and it would go to 100% CPU long enough to set off the alarm on the ASUS motherboard, but other than that, all 1/2/3 machines (at various times) have been humming along for over 3 years.
As for you, you might want to tap into the house's main AC and run a little 2-4" pipe for a bit of cooling, but that's as far as I'd go. I've had to replace a fan or two along the way, and one HD died, but that was an old (at the time) 6.8 GB IDE drive that probably had no business being in a 24/7/365 machine in the first place, so heat probably wasn't even the cause of that anyway. I haven't seen any more failures in that closet than I have with any other machine anywhere else in the house.
Laws of thermodynamics dictate that you can't put a window unit in there or anything (assuming this closet is not against an exterior wall)--that would heat up the rest of the house. IF you need cooling, run a duct from your existing AC. If you don't have AC at all, then a couple 6"-8" fans should move enough air. Assuming you don't have an airtight closet (louvered doors highly recommended!) you could have one or two fans drawing air up through the closet and exhausting into the attic.
Basically, think of the whole closet as being one giant computer case and plumb accordingly. And of course it wouldn't hurt to hit Radio Shack for a $20 digital indoor/outdoor thermometer to keep an eye on things.
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why not just cram an old refrigerator in there, mod the interior to support rack gear? you could even put that overclocked celeron 300a you used to want so bad up in the freezer, running at a cool even G (1 Ghz).
Find your nearest garden supply store that carries hydroponic gear. Now find the scruffiest employee therein. He'd be a great source of info on setting up ventilation systems in small rooms.
Literalism isn't a form of humor, it's you being irritating.