Re: "Hypothetical" Datacenter Overheating

[Glenn McGurrin via NANOG <nanog () nanog org>]

I'm actually referring to something like, I've not yet had a system 
where they have made sense, I mostly deal with either places where I 
have no say in the hvac or very small server rooms, but I've thought 
these were an interesting concept since I first saw them years ago.

https://www.chiltrix.com/server-room-chiller.html

quoting from the page:

The Chiltrix SE Server Room Edition adds a "free cooling" option to CX34.

Server rooms need cooling all year, even when it is cold outside. If you 
operate in a northern area with cold winters, this option is for you.

When outdoor temperatures drop below 38F, the CX34 glycol-water loop is 
automatically extended through a special water-to-air heat exchanger to 
harvest outdoor cold ambient conditions to pre-cool the glycol-water 
loop so that the CX34 variable speed compressor can drop to a very slow 
speed and consume less power. This can save about 50% off of it's 
already low power consumption without lowering capacity.

At and below 28F, the CX34 chiller with Free Cooling SE add-on will turn 
off the compressor entirely and still be able to maintain its rated 
cooling capacity using only the variable speed pump and fan motors. At 
this point, the CX34 achieves a COP of of >41 and EER of >141.

Enjoy the savings of 2 tons of cooling for less than 75 watts. The 
colder it gets, the less water flow rate is needed, allowing the VSD 
pump power draw to drop under 20 watts.

Depending on location, for some customers free cooling mode can be 
active up to 3 months per year during the daytime and up to 5 months per 
year at night.

On 1/17/2024 3:10 PM, Izaac wrote:
> On Wed, Jan 17, 2024 at 12:07:42AM -0500, Glenn McGurrin via NANOG wrote:
> > Free air cooling loops maybe? (Not direct free air cooling with air
> > exchange, the version with something much like an air handler outside with a
> > coil and an fan running cold outside air over the coil with the water/glycol
> > that would normally be the loop off of the chiller) the primary use of them
> > is cost savings by using less energy to cool when it's fairly cold out, but
> > it can also prevent low temperature issues on compressors by not running
> > them when it's cold.  I'd expect it would not require the same sort of
> > facade changes as it could be on the roof and depending only need
> > water/glycol lines into the space, depending on cooling tower vs air cooled
> > and chiller location it could also potentially use the same piping (which I
> > think is the traditional use).
>
> You're looking for these: https://en.wikipedia.org/wiki/Thermal_wheel
>
> Basically, an aluminum honeycomb wheel.  One half of its housing is an
> air duct "outside" while the other half is an air duct that's "inside."
> Cold outside air blows through the straws and cools the metal.  Wheel
> rotates slowly.  That straw is now "inside."  Inside air blows through
> it and deposits heat onto the metal.  Turn turn turn.
>
> A surprisingly effective way to lower heating/cooling costs.  Basically
> "free," as you just need to turn it on the bearing.  Do you get deposits
> in the comb?  Yes, if you don't filter properly.  Do you get
> condensation in the comb?  Yeah.  Treat it with desiccants.