Question for those who run computer rooms

[Russ Smith]

What temperature do you keep your room set at?

Just meeting with our PG&E rep because California is essentially going to start mandating peak usage rates for big users next year and we're big enough to be part of it. One of the things we did was discuss things like incremental changes to AC settings. Our computer room right now has 3 units in it, one is reading 69, one 64, one 66. The room is large enough that you have 3 distinct "environments" within it depending on which area (and which unit serves it) you are.

This guy told me Apple has a 70K square foot data center they keep set at 72 degrees. I've never worked with an IT person who didn't want it set to 68 or lower.

 

[Ryanwb]

Is this a "computer room" or a server room? Do you have raised floor?

There are basically two temperature settings to worry about. The most important is the ambient temperature, which is what the room's actual temperature is. You could run into issues where your AC unit just isn't powerful enough to cool the room and will basically never shut off. In my experience you won't start seeing issues until the ambient temp goes over 82 degrees. You'll have thermal shutdowns

72 degrees is good but I like 65 because you can have hot spots that can cause issues around the room. I usually take readings from multiple points in the room and don't like anything over 74 or 75

If you have a raised floor it is much much eaiser to cool the room

 

[Ryanwb]

So in closing I like to keep the ambient temp set at 68 or 70 which means you're AC will probably need to be set in the low 60's and will probably never shut off.

 

[Russ Smith]

So in closing I like to keep the ambient temp set at 68 or 70 which means you're AC will probably need to be set in the low 60's and will probably never shut off.

No raised floor, and yes server room is more accurate.

The real temp in the room is about 68 but as I say because of the location of the vents there's 3 distinct environments. I use a laser temp gun to take readings primarily at the return ducts and in general the air leaving the room by fan is 68 degrees. We're putting in 52-56 degree air depending on the unit.

Our units never go off, they can't, the demand never goes away. One of the 3 units is essentially only running the fan(return air) and first stage cooling because it's setpoint is higher than the room temp so it never gets warm enough that it kicks on. It's essentially there for redundancy if one unit goes down, and to help extract the hot air.

The PUC in California is going to mandate rate increases, essentially on peak demand days between 12 and 6pm, our rate will be FIVE times higher. This is supposed to come into play in 2007 so I'm trying to find ways to cut our usage and mitigate some of that. PG&E is actually fighting the PUC on the changes they want large customers on rate packages that allow them to voluntarily cut usage during critical peak times. Note the 5x cost is typically only going to be on specific days that due to temps or what have you create an abnormal usage. So it won't be 5x everyday. in 2005 there were 12 such days, but with business growing again they anticpate twice that many in 2007 when the plan would take effect.

 

[abomb]

The PUC in California is going to mandate rate increases, essentially on peak demand days between 12 and 6pm, our rate will be FIVE times higher. This is supposed to come into play in 2007 so I'm trying to find ways to cut our usage and mitigate some of that. PG&E is actually fighting the PUC on the changes they want large customers on rate packages that allow them to voluntarily cut usage during critical peak times. Note the 5x cost is typically only going to be on specific days that due to temps or what have you create an abnormal usage. So it won't be 5x everyday. in 2005 there were 12 such days, but with business growing again they anticpate twice that many in 2007 when the plan would take effect.

Not sure what you are running, but have you thought about server consolidation or remote hosting? When I was with IBM, we saw a continuous growth in both these areas.

 

[Russ Smith]

Not sure what you are running, but have you thought about server consolidation or remote hosting? When I was with IBM, we saw a continuous growth in both these areas.

I don't know what we're running either, I'm in facilities not IT. I talked to the IT manager but as I said, every IT manager I've ever worked with has insisted no warmer than 68 in a computer room. I'm just trying to get an idea if that's just a myth or not.

The theory is obvious, if the room is 65 and the HVAC goes off, it takes longer to become serious than if the room is 70 and the HVAC goes off. The problem that most IT managers don't accept is that running HVAC so that you can keep the room at 65, actually INCREASES the odds of it going down. What most do is oversize the unit to the room(more cooling than you need) and/or redundant units. We did both actually.

I don't know if other states are doing this or not but the PUC's proposal is outright ********. They will essentially use your past usage to establish "baselines". Then you will be given "credits" when you're below your baseline in peak hours, and charged the higher rate when you're above it during peak hours(on the heavy usage days for both). PG&E's point is that it actually encourages people to NOT cut usage until the new plan kicks in. Because if you do it now, your baseline will be lower when the plan kicks in so you'll get less credits, and go over your baseline a lot easier.

 

[bratwurst]

I was keeping our server room below 65 for a while and the ac guy got all over my case, because the condensation on the units started causing issues. He said, and I don't know how full of crap he was, but running the units to keep the air at 60 was not "conditioning" anymore, but actually refrigeration.

I think we keep our room at 68 - 70 now. And be sure that you have enough humidity in the room.

 

[Russ Smith]

I was keeping our server room below 65 for a while and the ac guy got all over my case, because the condensation on the units started causing issues. He said, and I don't know how full of crap he was, but running the units to keep the air at 60 was not "conditioning" anymore, but actually refrigeration.

I think we keep our room at 68 - 70 now. And be sure that you have enough humidity in the room.

Yep, when a unit is running constantly and putting out that cold of air, it can actually freeze itself up. It seems crazy in hot weather but I've seen it happen several times over the years. Unit dies, you up on the roof to see why and there's a pool of water leaking out of the unit where the coils are frozen over. The unit has to run so cold to keep the room at a low setting, that it freezes up.

The units probably has a condensation pump that couldn't keep up with the volume of condensation. They will often put stubs of open pipes in the ceiling in conspicuous places like the hallway, so that when this happens, water runs out and you see you have a problem. our old building for some godawful reason they put it a pan in there that was downhill not uphill of the stubbed pipe. So it would literally fill up and overflow, right near our servers. They had to go in and redo it to make sure it was flowing downhill to prevent that.

I got permission to bump the stats up 2 degrees and see if we have any negative impacts, so far nobody has called me in a panic this weekend so it appears not.