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Cooling the Server Room?
kolchak asks: "As the Australian summer heats up, we are looking at a cooling solution for our computer room. We have 4 racks (almost all full) with around 40 machines, switches, routers, 2 UPSs and 2 monitors. Unfortunately, its located in the middle of the office with no windows available for ventilation. We can vent the exhaust into the ceiling space which in turn is vented outside. Also, since the room is so small, we need to install any cooling device outside the room (a store room backs on which will house the cooling unit and potentially pipe hot / cold air through the wall). All the units we've seen so far need to be in the room, we just don't have the space. Anyone come across and solved this? Any ideas on good cooling units we can install easily and cheaply?"
We've got a similar problem, except that it's the winter time is the hardest to keep the room cool. During the summer, we run the air conditioner enough for the rest of the building that we can use the building's AC to keep the room nice and comfortable.
During the winter, however, the room is near the furnace, and I have a difficult time getting rid of the excess heat.
Our solution (such as it is) is to install a window unit AC in the room and vent the heat into the surrounding area. During the winter time, the heat zone that the room is in constantly runs the "fan only/no heat" option - it definitely helps the server room, but makes some of the other rooms less comfortable.
Our ultimate solution is to eventually move the server room, when that's possible.
A fine is a tax you pay for doing wrong and a tax is a fine you pay for doing all right.
one of the best solutions I have seen was at a local isp. They ran copper tubing just above the ceiling (hidden by the foam tiles) in a switchback layout similar to a radiator. They had a small pump just outside that moved water through both the internal and external radiators. It worked quite well and lowered the temperature in their main room by 20 degrees. Wasn't the prettiest thing with the tubing on the outside, but I'm sure you can find a way to hide it.
Ohhhh, look at all the pretty shiny things.
Hire your friendly local HVAC mechanic to cut the condenser coil off a big window A/C unit, and install it with a fan in your server room. The compressor and evaporator coil go in your storage room. A couple little 1/4" refrigerant pipes going through the wall and you're set.
You would probably be surprised how little a small custom cooling setup like this will end up being.
If you want to get really fancy, the refrigeration people can install a system that monitors the temperature and can page you (or an engineer) when the temperature gets too high. Large food establishments have this sort of thing. I've played with this setup, however, and I can tell you that the stuff the refrigeration engineers will install for you is no good, at least for this purpose. Their monitoring stuff can measure all sorts of refrigeration-engineering related things in addition to the temperature (use so the engineer can avoid a trip to the outdoor unit), but the equipment is overly expensive and the software is absolute shite (Windows 3.1 era stuff). Some computer/networking gear can measure temperature and shoot off a warning, but you probably want to measure the external ambient temperature as by the time the temperature rises inside the gear, you're already in trouble.
It might pay to hack together your own temperature monitoring setup (not too hard), but you definitely want to get a contractor to do the split system air conditioning.
They generate more heat than they take away, and you'll have trouble exhausting away all the heat they produce.
1 watt-hour == 3.41 BTUs. Say your typical rackmount PC, without monitor, draws around 100 watts, that's 341 BTUs. 40 machines plus two monitors and UPSs, plus some odd heat from lights and whatnot, call it about 14,000 BTUs. All that heat rises, and the best thing to do with it is duct it away, then replace it with cold air.
DO NOT SIMPLY DRAW IT INTO THE DROP CEILING, unless there is predictable airflow beyond the ceiling tiles, or a duct, with negative pressure relative to the server room. If there is not a definite exit from the ceiling, or if you're just pushing it up there and hoping it ends up someplace else, forget about it, it just lingers.
Portable AC-on-wheels: they generate decent BTUs removal, but their exchaust is ferocious. If you must use one, cut a hole in the wall for the exit hose, or mount it in a nearby window, just get it away. Don't even think of emptying it into the walls or drop-ceiling, it'll linger and boost the ambient temp.
If you have a window within 50 feet, you could mount a 20-25,000 BTU AC unit, and send the output through an insulated duct to the server room. If the duct runs more than 20-25 feet, you should put a draw fan on it to reduce back-pressure at the AC. Back-pressure can cause all sorts of trouble, so don't force through a tiny or too-long pipe.
Eh, if any of this seems confusing, hire a contractor!
The most important thing to do is monitor temperature in the room. If any of your PCs is recent, it'll have both "system" and "cpu" temp monitoring. There are temperature logging apps for *nix and Windows.
More beer please.
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