Re: rack power question

On 25 Mar 2008, at 09:11 , Dorn Hetzel wrote:

> It would sure be nice if along with choosing to order
servers with  
> DC or AC power inputs one could choose air or water
cooling.
>
> Or perhaps some non-conductive working fluid instead of
water.  That  
> might not carry quite as much heat as water, but it
would surely  
> carry more than air and if chosen correctly would have
more benign  
> results when the inevitable leaks and spills occur.

The conductivity of (ion-carrying) water seems like a
sensible thing  
to worry about. The other thing is its boiling point.

I presume that the fact that nobody ever brings that up
means it's a  
non-issue, but it'd be good to understand why.

Seems to me that any large-scale system designed to
distribute water  
for cooling has the potential for hot spots to appear, and
that any  
hot spot that approaches 100C is going to cause some
interesting  
problems.

Wouldn't some light mineral oil be a better option than
water?


Joe

Dorn Hetzel wrote:
> Of course, my chemistry is a little rusty, so I'm not
sure about the 
> prospects for a non-toxic, non-flammable,
non-conductive substance with 
> workable fluid flow and heat transfer properties 

Mineral oil?  I'm not sure about the non-flammable part
though.  Not all 
oils burn but I'm not sure if mineral oil is one of them. 
It is used 
for immersion cooling though.

Justin

While it has the potential to catch fire - it does however
work fine in my
car engine. 

-----Original Message-----
From: owner-nanogmerit.edu [mailto:owner-nanogmerit.edu] On Behalf Of
Justin Shore
Sent: 25 March 2008 14:20
To: Dorn Hetzel
Cc: nanog list
Subject: Re: rack power question


Dorn Hetzel wrote:
> Of course, my chemistry is a little rusty, so I'm not
sure about the 
> prospects for a non-toxic, non-flammable,
non-conductive substance 
> with workable fluid flow and heat transfer properties


Mineral oil?  I'm not sure about the non-flammable part
though.  Not all
oils burn but I'm not sure if mineral oil is one of them. 
It is used for
immersion cooling though.

Justin

Well, seeing as that most pad mounted transformers use
mineral oil as a
heat transfer agent (in applications up to and exceeding
230kv), I don't
suspect it is of issue.

However, we've all seen nice transformer fires.


> -----Original Message-----
> From: owner-nanogmerit.edu [mailto:owner-nanogmerit.edu] On Behalf
Of
> Justin Shore
> Sent: Tuesday, March 25, 2008 10:20 AM
> To: Dorn Hetzel
> Cc: nanog list
> Subject: Re: rack power question
> 
> 
> Dorn Hetzel wrote:
> > Of course, my chemistry is a little rusty, so I'm
not sure about the
> > prospects for a non-toxic, non-flammable,
non-conductive substance
> with
> > workable fluid flow and heat transfer properties

> 
> Mineral oil?  I'm not sure about the non-flammable part
though.  Not
all
> oils burn but I'm not sure if mineral oil is one of
them.  It is used
> for immersion cooling though.
> 
> Justin

Russia (or the USSR at that time) used to use liquid
graphite to cool their 
nuclear reactors, even thought it was flammable.... of
course that was what 
they were using in Chernobyl. 


-- 
Brian Raaen
Network Engineer
braaenzcorum.com

On Tuesday 25 March 2008, you wrote:
> 
> Dorn Hetzel wrote:
> > Of course, my chemistry is a little rusty, so I'm
not sure about the 
> > prospects for a non-toxic, non-flammable,
non-conductive substance with 
> > workable fluid flow and heat transfer properties

> 
> Mineral oil?  I'm not sure about the non-flammable part
though.  Not all 
> oils burn but I'm not sure if mineral oil is one of
them.  It is used 
> for immersion cooling though.
> 
> Justin
> 
>

I think the modern equivalent is HFE, manufactured by 3M;
HFE-7100 is
commonly used in the ATE industry for liquid cooling of test
heads.  It
is designed for very low temperatures (-135degC to 61degC)
so it might
not be suitable for general datacenter use.  HFE-7500 looks
like a
better fit. (-100degC to 130degC)



-----Original Message-----
From: owner-nanogmerit.edu [mailto:owner-nanogmerit.edu] On Behalf Of
Chris Adams
Sent: Tuesday, March 25, 2008 6:38 AM
To: nanog list
Subject: Re: rack power question


Once upon a time, Dorn Hetzel <dhetzelgmail.com> said:
> Of course, my chemistry is a little rusty, so I'm not
sure about the 
> prospects for a non-toxic, non-flammable,
non-conductive substance 
> with workable fluid flow and heat transfer properties


Fluorinert - it worked (more or less) for the Cray Triton.
--
Chris Adams <cmadamshiwaay.net>
Systems and Network Administrator - HiWAAY Internet Services
I don't
speak for anybody but myself - that's enough trouble.

On Mar 25, 2008, at 11:15 AM, Brian Raaen wrote:
>
> Russia (or the USSR at that time) used to use liquid
graphite to  
> cool their
> nuclear reactors, even thought it was flammable.... of
course that  
> was what
> they were using in Chernobyl.
>

The RBMK-1000 used graphite for moderation and water for
cooling.

Regards
Marshall

>
> -- 
> Brian Raaen
> Network Engineer
> braaenzcorum.com
>
> On Tuesday 25 March 2008, you wrote:
>>
>> Dorn Hetzel wrote:
>>> Of course, my chemistry is a little rusty, so
I'm not sure about the
>>> prospects for a non-toxic, non-flammable,
non-conductive  
>>> substance with
>>> workable fluid flow and heat transfer
properties 
>>
>> Mineral oil?  I'm not sure about the non-flammable
part though.   
>> Not all
>> oils burn but I'm not sure if mineral oil is one of
them.  It is used
>> for immersion cooling though.
>>
>> Justin
>>
>>