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Grizzly
03-01-2008, 08:09 PM
Blade Servers..
Has anyone besides the Viking and Myself noticed the
Increase in computer room A/C faults.
That can be directly linked to the latest trend of replacing Servers with the newer smaller and more powerful Blade Servers?
Grizzlyhttp://www.refrigeration-engineer.com/forums/images/icons/icon14.gif

Thermatech
03-01-2008, 10:16 PM
Most the ones I have been too lately have been newer R410a inverter units which have failed inverter or intermitent inverter faults.
Trouble is server rooms are often very small & standard comfort cooling split system wall mounts & cassettes tend to have supply air short circuit problems becase the air bounces off the server cabinets or the walls of the room.
One site I went to a few months back had 5 cassette units mounted in a room 10m long by 3m wide. This site was exceptional because 4 vapack humidifiers had been wall mounted in the room & the humidity was good at 50 to 60% so usual humidity problems & resulting coil frost were not an issue. But because the cassette units had poor air distribution & almost instant supply air recirculation the outdoor unit only ran for max 2 minuits.In that space of time the inverter ramped up, ramped down & stoped for 3 mins & then restarted again. All the units were doing this 24/7. Thats about 280 compressor starts per 24hrs.Thats 306,600 starts within the normal 3 year warrantee period !!!!!!!!!!!!!!!
The basic fact is that none of the manufacturers design standard split systems to make 280 starts per day 24/7.
For those who can remember the old Marstair high/low systems from the 70's & 80's will recall you could mix match them to make a cheap high sensible split system. But if they had supply air short circuit & constant stop start the largest single phase outdoor units would fail with fractured compressor pipe within a few months due to the constant stop start cycle.
Mitsubishi Daikin & LG all had exact same problem with R407c split systems installed in computer rooms.
But now with R410a inverter units when you would expect the compressor to slow down & run at slow speed forever we actually often find they still only run for 1 or two mins & then stop. Now the weekest link is not the refrigeration pipework which was fractured due to the large jolt of compressor start up every few minuits but now the inverter fails because it was never designed to start 280 times every day 24/7.
Contractors have always & will continue to mis apply standard comfort cooling split systems by installing them into computer rooms.Manufactures & distributors will continue to sell into this market because they are desperate to keep market share & dont want to loose sales.
So this age old problem keeps going around & around.
Good job too otherwise I would have to find somthing else to bang on about.
There are a number of other issues with this type of application but I can save for another post later.

The Viking
03-01-2008, 10:17 PM
I'm sulking now, trying to exclude me from this thread...

Anyway,

For a boring but informative (?) insight in to the future according to HP (NO, not the sauce, the computer guys), have a look at THIS (http://h30390.www3.hp.com/index.html?co=bladeanswers&jumpid=ex_r2548_go/bladeanswers)

Give them another couple of years and they migt not need us, they will do it all by themselves.

nike123
03-01-2008, 11:23 PM
Contractors have always & will continue to mis apply standard comfort cooling split systems by installing them into computer rooms.Manufactures & distributors will continue to sell into this market because they are desperate to keep market share & dont want to loose sales.


Right in bulls eye!:)
Nowadays, in my country, I personally, did not hear or know somebody, who sell or install, close control systems, although the company, in which until recently I was worked, represent the manufacturer of such equipment. Today IT companies most often looks for inverter split system, basically because their directors are yuppies whose only expertise is to make money fast before their short lived business die.

Latte
03-01-2008, 11:46 PM
I'm sulking now, trying to exclude me from this thread...

Anyway,

For a boring but informative (?) insight in to the future according to HP (NO, not the sauce, the computer guys), have a look at THIS (http://h30390.www3.hp.com/index.html?co=bladeanswers&jumpid=ex_r2548_go/bladeanswers)

Give them another couple of years and they migt not need us, they will do it all by themselves.


Paul Parez should have worn a jacket, He nearly has as much of a belly overhang than i do :D

"DSC" YEAH right :eek: i bet that isnt cheap, cant see that coming in on the installations we go to for a few years. It is refreshing to see HP pushing this though

Regards

Even Fatter boy

Plank!
04-01-2008, 12:06 AM
Not quite off topic, larger data centers have the same problems - lack of room/ducting etc for conventional AC.

A full rack of twin processor dual core blades will have a heat load of between 18 and 20KW at full load.

Take a look at this for a different approach to the cooling problem.
http://www.troxaitcs.com/aitcs/co2_trial/index.php
Star have been working with Trox on these units, pumping CO2 into a server rack door mounted evaporators at about 12c. The CO2 can be cooled with chilled water or a variation of stars turbocor powered chiller.
Not trying to sell anything here, I've worked on these systems and know how efficient they are.
However the systems i've worked on all have 15 or more of the door mounted evaps. each with 20KW of cooling

In the data centers that have added this system alongside conventional cooling they have an odd AC problem, the return air is now often colder than supply :eek:

Grizzly
04-01-2008, 12:11 AM
I'm sulking now, trying to exclude me from this thread...
.
Sorry Viking didn't mean to exclude you just did not know how to word it that's all!
I know from previous discussions that you had experianced a lot of similar issues to me.
I had no idea wether any of the other guys had also?
Incidently my source high up in Telecoms was also on about something called "the cube". Some sort of self contained refrigerated unit anyone know more?
(hopefully that's not the gist of your post Viking.
Tried to look at it earlier and sprogs demanded access to comp... just got back on!)
One of the other points is with previously well designed comp rooms. That struggle due to a blade server upgrade. The heat load is huge compaired to the units they are replacing ect
thermatech you have some very valid points there,
I totally agree there are some shody examples out there.
But companies like Airedale, Isovel, Denco ect ect. Make excellant Coms room equipment that may well of done the job pefectly untill some IT person carries out the afor mentioned. Usually at one end of the room!
Grizzlyhttp://www.refrigeration-engineer.com/forums/images/icons/icon14.gif

The Viking
04-01-2008, 01:16 AM
:D:D:D

We looked in to something called "cube" about a year ago.

It sounded good, all the cooling needed for one rack contained in a box above the rack.
OK, could have been a brilliant idea, until we realised it had a water cooled condensor (also in the same box!)
:eek: