On 8/23/11 9:12 AM, Jason Healy wrote:
We're a school with a small server room that we're trying to keep cool (about 4
racks, plus some telco gear). We have a dedicated AC unit in the room right
now, but it isn't able to keep up with the load in the space we have (the
airflow isn't great). Room is hovering around 75 F with AC on full blast 24/7.
On hot days it gets worse, and if the unit were to fail we'd go over temp
pretty quickly.
Called in a few vendors like APC and Leibert, and they're pitching an in-row or
wall-mount unit, but it's pretty pricey. Meanwhile, our regular AC vendor is
pitching another wall-mount unit similar to what we have in the room already:
http://www.e-comfortusa.com/products/mitsubishi-pkaa24ka4--puya24nha4-mr-slim--wall-mounted-mini-split-ac-cooling-only-system--24000-btu/5543
On the one hand, the "normal" unit is much cheaper. However, it lacks a few
nice features (SNMP reporting on errors, for example, should a pump fail). Given that
the unit we have can't keep up, I'm not sure if I want another of the same type.
Meanwhile, APC/Leibert are telling me that I'm crazy to consider another
"comfort" unit in this space, as they're not rated for this kind of use. The
units they sell are pretty and shiny, but are 5x the price (plus installation). I feel
like the in-row form factor might help us, as it would suck more hot air from the back of
the rack rather than let it mix into the room.
I need a little help cutting through the FUD on this one. Is "comfort" cooling so much
worse that it's worth the extra $$$ for a data-center unit? Since we're a school, I need to save
where I can (I'm also trying to get some better UPS in this room, so money I save on cooling can go
towards power). Since the space isn't a "proper" data center (no hot/cold aisle, no
raised floor, etc), I'm not sure where I should prioritize my funding.
Any thoughts for cooling on a tight budget?
Thanks,
Jason
Hi Jason,
Sounds like your server room is about the same as ours. 3.5 racks, 200
ft^2, no raised floor. We were running two of those mini-split-type
systems, one wall mounted Fujitsu and one ceiling mounted Sanyo. Had a
lot of problems with these (esp. the Sanyo), not the least of which was
they they don't work when the outdoor temp is very cold (< ~5 degrees F)
which is not unusual in Maine.
The ceiling mounted unit finally died completely, so we had the chance
to re-engineer. I looked at the APC in-row units, but found these to be
beyond our budget. We found a local HVAC contractor who had done other
small server rooms in the area. They spec-ed a consumer grade 5-ton
Coleman (aka York) unit with an indoor air handler. The cost was less
than 1/3 of what the comparable APC in-row solution would have been. We
were able to design the ducting for the air handler so that we could get
pretty close to a proper hot-aisle/cold-aisle configuration using
ceiling-mounted supply and return ducts. We also got a "low ambient
kit" to allow cold weather operation (no more January 3AM pager alerts,
yay!) The one thing we didn't get is humidity control, although that
was an option.
For SNMP temperature monitoring I use one of these:
http://www.networktechinc.com/enviro-mini.html . It works well and it's
pretty inexpensive.
The new A/C has been in service for a month now. Time will tell, but so
far I'm liking it.
Good luck with your quest.
Roy
--
Roy McMorran
Bar Harbor, ME
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