Computer room HVAC set points

[dschultz307]

I have a data center with three systems, 30, 20, and 20 ton Liebert DX units.

I have the room configured with hot aisle, cold aisle. Using this configuration we have been able to turn up the temp set point on the units to 74 degrees. The servers are happy and the system admins and not turning blue anymore.

But, our HVAC tech keeps turning the set points down to 68. When asked they say they run all computer rooms that way. Opinions? It just seems to use more energy and make the system work harder. Also seems to help over dehumidify too.

We even lost the 30 ton unit for a few days and the two 20s kept the servers cool enough even though we were reading 82 degree return air temps.

I know the set points are reading return air...so why set it so low? The unit will run 100% and never stage down.

[Airmechanical]

I have a data center with three systems, 30, 20, and 20 ton Liebert DX units.

I have the room configured with hot aisle, cold aisle. Using this configuration we have been able to turn up the temp set point on the units to 74 degrees. The servers are happy and the system admins and not turning blue anymore.

But, our HVAC tech keeps turning the set points down to 68. When asked they say they run all computer rooms that way. Opinions? It just seems to use more energy and make the system work harder. Also seems to help over dehumidify too.

We even lost the 30 ton unit for a few days and the two 20s kept the servers cool enough even though we were reading 82 degree return air temps.

I know the set points are reading return air...so why set it so low? The unit will run 100% and never stage down.

70 degrees@ 50% humidity is the norm for computer rooms!



.

[snipe70e]

It goes back to the old vacumn tube computers. Above 68 degrees you could get a stray electron, and thus courrupt data. There people out there who still think that computers will not work above 68 degrees.


Computers do work at high temp. Above 90 degrees will shorten the life of hard drives and other parts. Between 80 and 90 some life shortening can happen.

But the problem is convincing some people why computer room use to be kept low.

[Ausccn]

I have a data center with three systems, 30, 20, and 20 ton Liebert DX units.

I have the room configured with hot aisle, cold aisle. Using this configuration we have been able to turn up the temp set point on the units to 74 degrees. The servers are happy and the system admins and not turning blue anymore.

But, our HVAC tech keeps turning the set points down to 68. When asked they say they run all computer rooms that way. Opinions? It just seems to use more energy and make the system work harder. Also seems to help over dehumidify too.

We even lost the 30 ton unit for a few days and the two 20s kept the servers cool enough even though we were reading 82 degree return air temps.

I know the set points are reading return air...so why set it so low? The unit will run 100% and never stage down.

Comfortable for humans....comfortable for computers. The computer dudes always like it cold as that is what they have been taught. Computers now days can handle anything upto 26°C + (79°F) without any problems. It is just a waist of energy and an additional cause to green house gases.

The biggest problem is the correct air distribution and maintaining the correct temps at the servers. You can have a 21°C (70°F) temperature in the room measured by a room sensor but at the servers/rack it might be 28+°C (82°F) air distribution is the way to go!!!! My thoughts anyway!!!!!!

[Airmechanical]

Comfortable for humans....comfortable for computers. The computer dudes always like it cold as that is what they have been taught. Computers now days can handle anything upto 26°C + without any problems. It is just a waist of energy and an additional cause to green house gases.

The biggest problem is the correct air distribution and maintaining the correct temps at the servers. You can have a 21°C temperature in the room measured by a room sensor but at the servers/rack it might be 28+°C air distribution is the way to go!!!! My thoughts anyway!!!!!!

we seldom use Celsiuis here in America!

i wish that we did use the metric system for everything here, but we dont!


.

[Ausccn]

we seldom use Celsiuis here in America!

i wish that we did use the metric system for everything here, but we dont!


.

What I cant understand is that when I watch Discovery or Nat Geo and they are US doco's they usually talk in metric units. Is that just for the rest of the world????? or just us dudes down here in Aus!!!! Airmechanical...you should be out on the job by now....shouldn't you!!!!!! I'm just having a couple of good Aussie beers after a hard days work.......

[Airmechanical]

Airmechanical...you should be out on the job by now....shouldn't you!

you sound like my old boss!

maybe thats why i fired him



.

[Ausccn]

you sound like my old boss!

maybe thats why i fired him



.

he must of been a great dude....!!!!

[Randy S.]

Celsius?

It's those dang British Thermal Units I keep having trouble with.

They always come with metric threads.

Then there's all this talk about sub cooling, and I ain't never been in the Navy.

[dschultz307]

Thanks for the discussion.

Actually it is the computer dudes that are turning blue and freezing to death in the computer rooms. Actually had HP engineers lay cardboard on the floor to block the airflow!

I figured if the intake air to the servers in the the cold aisle was cool enough then return air temps could run higher that 72 without beating up the HVAC equipment.

It took a while to explain that the hot aisle should be HOT!

[CRAC Dealer]

72-75*F 50% is fine.

I set them for 73*F at start up. 68* is over kill and will cause higher stress on the units. Maybe they got sick of hearing about short cycle alarms?

[tgig]

doesn't Liebert "stress" low humidity, exactly how do you over dehumidify?
If the zods are OK with the setup, and the room requires special handling[hence your bill], then who's giving a key to the light bulb changers anyway? Where are their orders coming from?

[Tommy1010]

All of ours are also between 70F and 73F. Computers just keep sending heat. Its not like cooling off an empty room where the T stat eventually gets satisfied. This is a never ending marathon for the a/c.

[Ausccn]

doesn't Liebert "stress" low humidity, exactly how do you over dehumidify?
If the zods are OK with the setup, and the room requires special handling[hence your bill], then who's giving a key to the light bulb changers anyway? Where are their orders coming from?

So Cany You explain this???
BSME;BAmkt;AAS,comm.HVAC; PLT,NEC;Op.Engr.HP,A&B;USN,BPE,EN; Emerson-Liebert EUSAF1;Sales Awards 6yr ?????? I'm only a dumb HVAC controls engineer with 25 years experience.....!!!!!

[cateyes]

between 70=72...

[Airmechanical]

doesn't Liebert "stress" low humidity, exactly how do you over dehumidify?
If the zods are OK with the setup, and the room requires special handling[hence your bill], then who's giving a key to the light bulb changers anyway? Where are their orders coming from?

ya, low humidity kills computer servers!



.

[ssmechservices]

72F 50% Hum

[whec720]

70 to 72 degree with a RH 45 to 50%. Keep those dry bulb temps. Remember, humidity is relative to the temperature you are at.

[The Doctor]

Speaking of overcooling, there are data center managers who would insist that we keep their rooms in the low 60s (temperature), despite our insistence that the humidity would spike.

Their heat load was strong and we wrestled with humidity issues.

Money was no object, except when nickel and diming us would give him something to crow about. After all, he had to justify his existence too.

You could see your breath when working on the condensate pumps under the floor.

Anyway, the folks that work in those rooms usually have a cardigan or two hanging on the back of their chairs. And the managers rightly don't give a rip whether or not their peeps are cold or not. Those rooms are not designed for people.

[whec720]

Ain't that the truth.....only the server racks matter. Everything else, is exspendable.