Cooling a small server room

ochadd

ochadd

[H]ard|Gawd
Joined
May 9, 2008
Messages
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Good morning everyone,
Looking for a very reliable AC unit recommendation to cool a small server room. I've got a fairly small server room at a location that is currently cooled with a 7 year old, 2 ton Mitsubishi mini-split. That unit keeps shutting down on me whenever outside temps dip below 0 F. Cooling capacity is plenty. The HVAC guys only want to replace it since they've already installed a low ambient kit without success. I'm sick of coming in at 2 am and during snow storms...

Machines include:
6 dual quad core servers
3 dual six core servers
2 x 24 disk bays for the SAN
1 phone system
3 routers
8 24 port layer 3 switches
1 24 port POE injector

The HVAC guys have made some recommendations but I'm hoping to hear what some other IT folks are running before committing. Price is a big issue but if there's a "standard" for something like this I can probably get it approved.
Thanks
 
Given the low outside temperatures you could just pipe in air from outside - that could save a lot of money in terms of air conditioning.

This assumes you are in an area where the outside temperature is reasonably low all year round.
 
We're in the middle of trying to get solutions for our main "datacenter" and smaller 1-rack locations. The variance in cost and equipment has been huge. Cheapest is $40k, most expensive is $480k.

It would be helpful to know if you're looking at a "big" system or a "small" system.

If you're going Big for future expansion - you should put some "free" glycol cooling as well. You still need a full A/C unit that will be up to cooling it down when it's 110 outside, but in SD you'll likely get around 200 "free" cooling days (it still has to operate a pump and fan, but it's less than 5% the energy of running an A/C unit).

If you're going "small", a half-rack sized split system could probably take care of you just fine - maybe even a wall-mount split would work. APC has some decent options in this space.
 
Since you are just using a simple mini split... I would highly recommend MovinCool units as your alternative. They are cheaper than a mini split (if you factor installation costs) and they are brain dead simple to use and bulletproof. You would need to duct to the outside for your hot air but other than that it's pretty straight forward.


The problem you have is common on air cooled cooling systems in cold weather, they are not designed for such a situation (generally air cooled condensers are used in warm weather). Your way around it is something like a moving cool, or a glycol based drycooler outside (has the opposite effect in the summer), or installing leetemp tanks on your outside air cooled condenser (I don't believe there are any of these solutions for your mini-splits).
 
Innocence said:
We're in the middle of trying to get solutions for our main "datacenter" and smaller 1-rack locations. The variance in cost and equipment has been huge. Cheapest is $40k, most expensive is $480k.

It would be helpful to know if you're looking at a "big" system or a "small" system.

If you're going Big for future expansion - you should put some "free" glycol cooling as well. You still need a full A/C unit that will be up to cooling it down when it's 110 outside, but in SD you'll likely get around 200 "free" cooling days (it still has to operate a pump and fan, but it's less than 5% the energy of running an A/C unit).

If you're going "small", a half-rack sized split system could probably take care of you just fine - maybe even a wall-mount split would work. APC has some decent options in this space.
Click to expand...

I'm looking for a small system. The systems are already oversized so maybe 2 more servers and a couple switches in a year +. The current unit is wall mounted with an outside jobbie attached through just a few pipes. The HVAC guys are recommending a 2.5 ton Fujitsu mini-split with AC only. The old unit has the ability to heat which is not needed. Around $3000 installed is what they are thinking.

Edit: I really like the specs on that MovinCool unit. Will check them out.
 
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XL5 said:
Given the low outside temperatures you could just pipe in air from outside - that could save a lot of money in terms of air conditioning.

This assumes you are in an area where the outside temperature is reasonably low all year round.
Click to expand...

That is a really bad idea. Ever heard of condensation?

OP, Tripp Lite make a great spot cooler that dehumidifies and vents hot air and moisture out. Perfect for small installs where a separate condenser is not possible.

http://www.tripplite.com/en/products/model.cfm?txtModelID=4462

I have used them in a few places where a real AC unit was unaffordable or not possible.

Oh and that thing will chill an entire floor if you let it.
 
Sounds like you just need to get a cold weather kit added to the existing HVAC unit. I run a 3 ton unit for our server room at work and the cold weather kit allows it to work well below zero (I'm in Wisconsin).
 
Krazypoloc said:
Sounds like you just need to get a cold weather kit added to the existing HVAC unit. I run a 3 ton unit for our server room at work and the cold weather kit allows it to work well below zero (I'm in Wisconsin).
Click to expand...
We have a "cold weather kit" on our current 6 ton unit too (Central Canada). All it does is circulate warm fluid around the condenser to keep it from freezing up.

It doesn't really work work a damn - we still have at least a dozen failures every winter. The unit is finally out of warranty (10 years) so the penny-pinchers will let us replace it. Which is why we're getting glycol.
 
Krazypoloc said:
Sounds like you just need to get a cold weather kit added to the existing HVAC unit. I run a 3 ton unit for our server room at work and the cold weather kit allows it to work well below zero (I'm in Wisconsin).
Click to expand...

Our guys said they did install one. They called it a low ambiant kit and was ordered through the mfg Mitsubishi. It still craps out on me.
 
schizrade said:
That is a really bad idea. Ever heard of condensation?

OP, Tripp Lite make a great spot cooler that dehumidifies and vents hot air and moisture out. Perfect for small installs where a separate condenser is not possible.

http://www.tripplite.com/en/products/model.cfm?txtModelID=4462

I have used them in a few places where a real AC unit was unaffordable or not possible.

Oh and that thing will chill an entire floor if you let it.
Click to expand...

I use one of those in a small room works great
 
Could be that your unit is being overtaxed or is faulty then. I would suggest getting a capacity test done before you go buy something. Nothing worse than being stuck with a unit that isn't large enough to cool your room.
 
I know this is a month later but it might still help. Our unit has the same issue. For us it would cut out after it got to about 90 degrees, which in New Mexico happens daily for about 2 or 3 months. It turned out to be a faulty transformer in the unit. When they replaced it they used a transformer that now cuts out below 0 degrees. This only happens once every few years so not a problem for us, but I know what needs to be replaced if we want that fixed. Its worth checking out before replacing the entire unit.
 
We have a mitsubishi mini-split system for AC cooling only. I live in West Texas where we can get to 0 degrees at night and 110 in the summer as well. The mini-split has worked perfect.
 
We're going with a 2 ton Fujitsu mini-split that does AC only. Should be installed this week. One of the HVAC guys here explained it like this..
AC units have a 12-15 year lifespan around here normally. They only need to cycle on and off for 4-5 months and only run a heavy load for 3 or so months of the year. In the server room it runs 24/7 or very near it. It's lasted well beyond it's intended limits.
 
schizrade said:
That is a really bad idea. Ever heard of condensation?

OP, Tripp Lite make a great spot cooler that dehumidifies and vents hot air and moisture out. Perfect for small installs where a separate condenser is not possible.

http://www.tripplite.com/en/products/model.cfm?txtModelID=4462

I have used them in a few places where a real AC unit was unaffordable or not possible.

Oh and that thing will chill an entire floor if you let it.
Click to expand...

I have one of these units in a much smaller room. I don't think one would handle the given load.
 
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