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From: Paul J Gans on 5 Aug 2010 12:52
Vahis <waxborg(a)gmail.com.invalid> wrote:
>On 2010-08-05, houghi <houghi(a)houghi.org.invalid> wrote:
>> Bernd Felsche wrote:
>>> Artificial intelligence conditioning? :-)
>>
>> Yeah. :-D
>>
>>> Nobody's mentioned inlet air temperatures.
>>>
>>> The other thing that can be managed is humidity. If inlet air is
>>> kept at between 18 and 24°C and 60 to 80% RH, then there is plenty
>>> of thermal capacity available to minimise the temperature rise of
>>> air moving through the equipment.
>>
>> I understand that and for me that is part of airconditioning. It not
>> only adds or removes heat. It can also add or remove humidity, dust,
>> odor, ...
>>
>>> As for quiet and cool rack cabinets, they can be very expensive and
>>> quite inefficient to operate. <snip>
>>
>> The obvious better way would be to have a seperate room and aircondition
>> that. That would be my ideal solution. Make a room the size of a broom
>> closet, put airco and a rack mount in there.
>>
>> Then have a KVM for, well keyboard, video and mouse. Best run that over
>> IP. Then also have a sort of NAS, but with a DVD/writer and USB
>> connectors run also over IP.
>>
>> As the IP could be wireless, all you need is cables for your sound and
>> you are done.

>Sound can be (mine is) wireless, too :)

>> All I now need is a house to put it in and the money to buy it.
>>
>House is good. I'd like to have one of my own, too.

>I'm aiming to this one:
>http://kuluttaja.etuovi.com/omakotitalo/espoo/14648

Very nice!

--
--- Paul J. Gans
From: Moe Trin on 5 Aug 2010 15:36
On Thu, 05 Aug 2010, in the Usenet newsgroup alt.os.linux.suse, in article
<hmoqi7x0pf.ln2(a)innovative.iinet.net.au>, Bernd Felsche wrote:

>houghi <houghi(a)houghi.org.invalid> wrote:

>> Bernd Felsche wrote:

>>> Nobody's mentioned inlet air temperatures.

>>> The other thing that can be managed is humidity. If inlet air is
>>> kept at between 18 and 24�C and 60 to 80% RH, then there is plenty
>>> of thermal capacity available to minimise the temperature rise of
>>> air moving through the equipment.

We don't even keep our server rooms that cool - although the air
conditioner is pumping air at 5C/41F. With a room temperature of
24C/75F, the humidity percentage will be in the single digits. Cold
air can't hold as much moisture as warm air. With 24C and 60% air,
any surface at or below 18.6C will be wet with condensate.

>>I understand that and for me that is part of airconditioning. It not
>>only adds or removes heat. It can also add or remove humidity, dust,
>>odor, ...

If your air conditioner is adding dust, replace the filters. If it's
adding odor, call a service tech, as you've got something seriously
wrong with it. Air conditioning removes humidity - it gets condensed
out as the air moves over the cooling coils. Adding moisture to the
air is usually done separately.

>Computers don't do well in dry air. It tends to accummulate a static
>charge. Moisture content allows the charge to dissipate.

In my house (near Phoenix, about 360 miles/600 KM East of Los Angeles)
with 84000 BTU/H = 24.6 KW of central air conditioning, I can bring
the interior temperatures down to 27C/81F during the day when it's a
bit over 45C/113F outside. As the outside air is already below a 20%
RH, there are two humidifiers adding 15 liters/4 USGal of water to the
air every day. This brings the interior RH up into the 40-50% range.

>It takes a more-than-usual airconditioning system to also control
>humidity. i.e. one that costs about as much as the equipment being
>protected. Possibly plumbing to a mains water supply if the
>conditioned room leaks air.

Leaking air has nothing to do with it. It's a natural function of
blowing moist air over a cold surface - it's called condensation.
As for costs - the compressors and external (exhaust) heat exchanger
alone are over US$10000 and the interior heat exchanger, blowers and
duct-work add another US$5000. Then you turn the air conditioners on
and start paying for electricity.

>Dust is usually not a problem with modern computers; unless it's
>caked onto ventilation grilles, fans or heatsinks. A couple of
>servers that I manage had suprisingly-little dust build up inside
>after 4 years of operation in an open-plan, carpeted office
>environment.

Ah, but the humidity is high enough that you don't have as much of
a dust problem. I replace the dust filters on the air conditioners
five times a year. I understand it rains in Perth - I've had 10.42"
(265 mm) of rain at my house so far this year, and that's about 40%
above normal for this time of year. That's also about twice what the
official weather station in town received. My ten year running
average is 10.70 inches (272 mm) for the entire year.

Old guy
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